Calculations in input text fields

Question

Hello,
I'm making an engineering game. Students need to input force
equations and to check the equation is right it has to add up to
zero. There are two input text fields, one the student sees with
the force values expressed in letters like HA, VA, and MA, and one
hidden field where the values are expressed as numbers. They also
input operators as part of the equation. I need to make it so when
they click a button to check if their equation is correct, the
contents of the text field are calculated to see if the equation
adds up to zero. I know you can express the contents as a number
with say Number (this.my_hidden_text.text), but how do I get the
operators in the equation, which are +, -, *, /, (, ), and ^ to
mean something and do what they're supposed to?
Any assistance would be most welcome.
Thank you for your time,
Beatie3

Answer 1

Thank you for your quick response. Would you mind explaining
more how to use the strings method to find the operators, please?
It's a bit messy but my code currently looks like this:
stop();
//hide stuff
this.tickb._visible = false;
this.crossb._visible = false;
//declare the variables
var check1:Number = parseInt(display_secret.text);
var display1 = "";
var display_secret = "";
//function for the calculation
function onCalculate() {
if(this.display_secret = 0){
this._parent.tickb._visible = true;
this._parent.crossb._visible = false;
} else {
this._parent.crossb._visible = true;
this._parent.tickb._visible = false;
check02_btn.onRelease = function():Void {
trace(display1);
trace(check1);
if(check1 == 0){
this._parent.tickb._visible = true;
this._parent.crossb._visible = false;
} else {
this._parent.crossb._visible = true;
this._parent.tickb._visible = false;
//load external images
pic04_container.loadMovie("fig_3_1a.gif");
//takes you back to the previous scene
back02_btn.onRelease = function() {
gotoAndStop("Scene 2", 1);
//Takes you home
home02_btn.onRelease = function() {
gotoAndStop("Scene 1", 1);
//moves to the next scene
next02_btn.onRelease = function() {
gotoAndStop("Scene 3a", 1);
//calculator buttons workings
left_btn.onRelease = function() {
display1 = display1+ "(";
display_secret = display_secret + "(";
plus_btn.onRelease = function() {
display1 = display1+"+";
display_secret = display_secret +"+";
times_btn.onRelease = function() {
display1 = display1+"*";
display_secret = display_secret +"*";
right_btn.onRelease = function() {
display1 = display1+")";
display_secret = display_secret +")";
minus_btn.onRelease = function() {
display1 = display1+"-";
display_secret = display_secret +"-";
peek_btn.onRelease = function() {
display1 = display1+"^";
display_secret = display_secret +"^";
slash_btn.onRelease = function() {
display1 = display1+"/";
display_secret = display_secret +"/";
ha_btn.onRelease = function() {
display1 = display1+"HA";
display_secret = display_secret +"108";
va_btn.onRelease = function() {
display1 = display1+"VA";
display_secret = display_secret +"0";
ma_btn.onRelease = function() {
display1 = display1+"MA";
display_secret = display_secret +"1296";
c_btn.onRelease = function() {
display1 = "";
display_secret = "";
vd_btn.onRelease = function() {
display1 = display1+"VD";
display_secret = display_secret +"0";
w_btn.onRelease = function() {
display1 = display1+"w";
display_secret = display_secret +"12";
a_btn.onRelease = function() {
display1 = display1+"a";
display_secret = display_secret +"18";
b_btn.onRelease = function() {
display1 = display1+"b";
display_secret = display_secret +"9";
thank you very much for your help,
Beatie3