 # Can you critique my calculator?

Hi. This is just straight javascript code at this point. I decided i wanted to build the calculator using closures. My intention was to have a bunch of functions which exactly replicated the behavior of a button on a calculator. That way when I go to build the interface I can just call functions from the html elements i use to draw the interface.

I’m still tweaking it and I’m not happy with how everything works. For example, I just got decimals working. The way calculators insert decimal places is hard to translate into code. I have it working but I think theres a more elegant solution. Maybe if I keep everything in scientific notation until it gets displayed.

``````function createCalculator() {
var a = 0;
var b = 0;
var operatorSet = "none";
var hasCalculated = false;
var decimalFlag = false;
var deci = 0;
var operator;
var operators = {
subtract: function(){a -= b; display("subtract", a);},
multiply: function(){a = a*b; display("multiply", a);},
divide: function(){a = a/b; display("divide", a);},
}

function display(name, value) {
if (name && value) {
console.log(a);
}
if (name && !value) {
console.log(name + ": " + b);
}
}

function clear() {
a = 0;
b = 0;
operatorSet = "none";
display(clear.name);
}

function set(value) {
if (hasCalculated == true && operatorSet == "none") {
a = value;
b = 0;
hasCalculated = false;
} else if (operatorSet == "none") {
value = value.toString();
a = a.toString();
a = a.concat(value);
a = parseFloat(a);
if (decimalFlag == true) {
a = a * Math.pow(10, deci);
decimalFlag = false;
}
} else if (operatorSet != "none") {
value = value.toString();
b = b.toString();
b = b.concat(value);
b = parseFloat(b);
}

}

function print() {
console.log("a: " + a +"\nb: "+ b + "\noperator: " + operatorSet);
}

function decimal() {
deci = -(a.toString().length);
decimalFlag = true;
}

return {
clear: clear,
print: print,
set: set,
decimal: decimal,
selectSubtract: function() {operator = operators.subtract; operatorSet = "Subtract";},
selectMultiply: function() {operator = operators.multiply; operatorSet = "Multiply";},
selectDivide: function() {operator = operators.divide; operatorSet = "divide";},
calculate: function() {operator(); operatorSet = "none"; hasCalculated = true;},
}
};

// Example:
calc = createCalculator(); // instantiate calc function
calc.set(3); // set a = 3
calc.decimal(); // set decimal place
calc.set(1); // set a = 3.1 (concat 1 to end of number)
calc.set(4); // set a = 3.14 (concat 4 to end of number)
calc.selectMultiply(); // select multiply operator
calc.set(2); // set B = 2
calc.print(); // print A,B, and operator (for testing)
calc.calculate(); // Calculate result and store as A
calc.calculate(); // Calculate result times b again (just like a real calculator)``````