316 lines
9.9 KiB
HTML
Executable File
316 lines
9.9 KiB
HTML
Executable File
<HTML>
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<head><title>Java script rekenmachine</title>
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</head>
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<body background="geel.gif">
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<body bgcolor="ffffff" link="ffff00" text="ff0000"><p><center><h2>
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<font face="Trebuchet MS">Java script: rekenmachine</center></h2></p><p><center>
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<SCRIPT LANGUAGE="LiveScript">
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var acc = 0;
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var oper = " ";
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var startnum = true;
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var decpoint = false;
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var errorstate = false;
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MAXLEN = 14;
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function IsNumeric(num)
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{ var idx = 0;
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var ch = "";
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var foundpoint = false;
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for (idx = 0; idx < num.length; idx++) {
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ch = num.substring(idx, idx +1 );
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if ((ch < "0") || (ch > "9")) {
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if ((ch == ".") && (!foundpoint)) {
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foundpoint = true;
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continue;
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} else {
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if ((ch == "-") && (idx == 0)) {
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continue;
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}
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}
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return false;
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}
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} // for idx
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return true;
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}
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//
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// ContainsChar - check if a string contains a certain char
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//
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function ContainsChar(str, ch) {
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var idx;
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for (idx = 0; idx < str.length; idx++) {
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if (str.substring(idx, idx + 1) == ch) {
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return true;
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}
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} // for idx
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return false;
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}
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//
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// ContainsDecimalPoint - check if a number string contains a decimal point
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//
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function ContainsDecimalPoint(num) {
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return ContainsChar(num, ".");
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}
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//
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// DisplayChanged - the display was explicitly changed, so check if it is valid
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//
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function DisplayChanged(form, display) {
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if (!errorstate) {
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if (IsNumeric(display.value)) {
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display.defaultValue = display.value;
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startnum = false;
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decpoint = ContainsDecimalPoint(display.value);
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} else {
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alert("You must enter a numeric value here.");
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display.value = display.defaultValue;
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}
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} else { // errorstate
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alert('An error has occured. Press the "AC" button.');
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}
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}
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//
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// NumPressed - a digit button was pressed, add it to the current display
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//
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function NumPressed(form, digit) {
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if (!errorstate) {
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if ((digit !=0) || (form.display.value != "0")) {
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if (startnum) { // need to put a new number on the display (e.g. after "=")
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form.display.value = eval(digit);
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} else {
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if (form.display.value.length < MAXLEN) {
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form.display.value = form.display.value + digit;
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} // enough room to put new digit
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} // add the digit
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startnum = false;
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form.display.defaultValue = form.display.value;
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} // not trying to add leading zeros
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} else { //errorstate
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alert('An error has occured. Please press the "AC" button');
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}
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}
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//
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// ChangeSign - "+/-" button was pressed, change sign of current display
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//
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function ChangeSign(form) {
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if (!errorstate) {
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if (form.display.value != "0") {
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if (eval(form.display.value) < 0) { // negative no problem
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form.display.value = 0 - eval(form.display.value);
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} else { // positive, make sure it's not too long
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if (form.display.value.length < MAXLEN)
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form.display.value = 0 - eval(form.display.value);
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} // positive
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form.display.defaultValue = form.display.value;
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startnum = false;
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} // not 0, can be negated
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} else { // errorstate
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alert('An error has occured. Please press the "AC" button');
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}
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}
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//
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// PointPressed - the decimal dot was pressed, add it to number and start putting disits after it
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//
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function PointPressed(form) {
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if (!errorstate) {
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if ((!decpoint) && (form.display.value.length < MAXLEN - 1)) {
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form.display.value = form.display.value + ".";
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form.display.defaultValue = form.display.value;
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decpoint = true;
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startnum = false;
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} // decimal point not already present
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} else { // errorstate
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alert('An error has occured. Please press the "AC" button');
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}
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}
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//
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// ClearAll - "AC" button was pressed, restart the calculator
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//
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function ClearAll(display) {
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display.value = "0";
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display.defaultValue = "0";
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decpoint = false;
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acc = 0;
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oper = " ";
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startnum = true;
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errorstate = false;
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}
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//
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// ClearNum - "C" button was pressed, clear only current number on display
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//
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function ClearNum(display) {
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if (!errorstate) {
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display.value = "0";
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display.defaultValue = "0";
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decpoint = false;
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startnum = true;
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} else { // errorstate
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alert('An error has occured. Please press the "AC" button');
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}
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}
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//
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// RemoveZeros - remove leading zeros after a decimal point from a number string
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//
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function RemoveZeros(num) {
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var idx;
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if (ContainsChar(num, ".")) {
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idx = num.length - 1;
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ch = num.substring(idx, idx + 1);
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while((idx > 0) && (ch == "0")) {
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idx--;
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ch = num.substring(idx, idx + 1);
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}
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num = num.substring(0, idx + 1);
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// get rid of a trailing decimal point, if it remained hanging after the torture ...
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if (num.substring(num.length - 1, num.length) == ".") {
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num = num.substring(0, num.length - 1)
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}
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} // num contains a decimal point
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return num;
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}
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//
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// CalcDisplay - calculate the new display using the accumulator and the previous operator
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//
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function CalcDisplay(display) {
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if (oper == "+") {
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display.value = acc + eval(display.value);
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} else if (oper == "-") {
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display.value = acc - eval(display.value);
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} else if (oper == "*") {
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display.value = acc * eval(display.value);
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} else if (oper == "/") {
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if (display.value == "0") {
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display.value = "ERROR !"
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errorstate = true;
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} else {
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display.value = acc / eval(display.value);
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}
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}
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if (!errorstate) {
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if ((eval(display.value) >= eval("1e" + MAXLEN)) || (eval(display.value) <= eval("-1e" + (MAXLEN - 1)))) {
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display.value = "ERROR !";
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errorstate = true;
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} else {
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if (!ContainsChar(display.value, "e")) { // not exponential format
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if (display.value.length > MAXLEN) {
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// number is in permited range, so extra digits are after decimal point
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// truncate extra digits
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display.value = display.value.substring(0, MAXLEN);
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// get rid of a hanging decimal point
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if (display.value.substring(MAXLEN - 1, MAXLEN) == ".") {
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display.value = display.value.substring(0, MAXLEN - 1);
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} else {
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// get rid of trailing zeros
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display.value = RemoveZeros(display.value);
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}
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} // string too long
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} else { // exponential format
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// Numbers smaller than 0.00001 are represented in exponential notation by the browser.
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// A piece of code to translate them to fix notation should be put here.
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// This is getting *much* too boring for me, so I leave it as is.
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// If anyone has the will power to write it, I'll be glad to include it ...
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} // exponential format
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} // not too high or low
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} // no error yet (division by zero)
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display.defaultValue = display.value;
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}
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//
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// OperPressed - calculate the new display and move it to the accumulator
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//
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function OperPressed(form, newoper) {
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if (!errorstate) {
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CalcDisplay(form.display);
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oper = newoper;
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acc = eval(form.display.value);
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startnum = true;
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decpoint = false;
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} else { // errorstate
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alert('An error has occured. Please press the "AC" button');
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}
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}
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//
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// CalcResult - the "=" button was pressed, put result on display
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//
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function CalcResult(form) {
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if (!errorstate) {
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CalcDisplay(form.display);
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oper = " ";
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acc = 0;
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startnum = true;
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decpoint = false;
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} else { // errorstate
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alert('An error has occured. Please press the "AC" button');
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}
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}
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// End of hiding script from browsers which do not support it. -->
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</SCRIPT>
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<FORM>
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<TABLE BORDER=2>
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<TR>
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<TD ALIGN=MIDDLE>
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<INPUT TYPE="text" SIZE=15 NAME="display" VALUE="0" ONCHANGE="DisplayChanged(this.form, this.form.display)">
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</TD>
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</TR>
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<TR>
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<TD>
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<TABLE BORDER=1>
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<TR>
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<TD> <INPUT TYPE="RADIO" CHECKED ONCLICK="history.go(-1)"> </TD>
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<TD> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" C " ONCLICK="ClearNum(this.form.display)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE="AC" ONCLICK="ClearAll(this.form.display)"> </TD>
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</TR>
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<TR>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 1 " ONCLICK="NumPressed(this.form, 1)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 2 " ONCLICK="NumPressed(this.form, 2)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 3 " ONCLICK="NumPressed(this.form, 3)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" + " ONCLICK='OperPressed(this.form, "+")'> </TD>
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</TR>
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<TR>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 4 " ONCLICK="NumPressed(this.form, 4)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 5 " ONCLICK="NumPressed(this.form, 5)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 6 " ONCLICK="NumPressed(this.form, 6)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" - " ONCLICK='OperPressed(this.form, "-")'> </TD>
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</TR>
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<TR>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 7 " ONCLICK="NumPressed(this.form, 7)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 8 " ONCLICK="NumPressed(this.form, 8)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 9 " ONCLICK="NumPressed(this.form, 9)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" X " ONCLICK='OperPressed(this.form, "*")'> </TD>
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</TR>
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<TR>
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<TD> <INPUT TYPE="BUTTON" VALUE="+/-" ONCLICK="ChangeSign(this.form)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" 0 " ONCLICK="NumPressed(this.form, 0)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" . " ONCLICK="PointPressed(this.form)"> </TD>
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<TD> <INPUT TYPE="BUTTON" VALUE=" / " ONCLICK='OperPressed(this.form, "/")'> </TD>
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</TR>
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<TR ALIGN=CENTER>
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<TD COLSPAN=4> <INPUT TYPE="BUTTON" VALUE=" = " ONCLICK="CalcResult(this.form)"> </TD>
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</TR>
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</TABLE>
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</TD>
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</TR>
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</TABLE></body>
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</HTML> |