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function MathSolver() { | |
this.infixToPostfix = function(infix) { | |
var outputQueue = ""; | |
var operatorStack = []; | |
var operators = { | |
"^": { | |
precedence: 4, | |
associativity: "Right" | |
}, | |
"/": { | |
precedence: 3, | |
associativity: "Left" | |
}, | |
"*": { | |
precedence: 3, | |
associativity: "Left" | |
}, | |
"+": { | |
precedence: 2, | |
associativity: "Left" | |
}, | |
"-": { | |
precedence: 2, | |
associativity: "Left" | |
} | |
} | |
infix = infix.replace(/\s+/g, ""); | |
infix = infix.split(/([\+\-\*\/\^\(\)])/).clean(); | |
for(var i = 0; i < infix.length; i++) { | |
var token = infix[i]; | |
if(token.isNumeric()) { | |
outputQueue += token + " "; | |
} else if("^*/+-".indexOf(token) !== -1) { | |
var o1 = token; | |
var o2 = operatorStack[operatorStack.length - 1]; | |
while("^*/+-".indexOf(o2) !== -1 && ((operators[o1].associativity === "Left" && operators[o1].precedence <= operators[o2].precedence) || (operators[o1].associativity === "Right" && operators[o1].precedence < operators[o2].precedence))) { | |
outputQueue += operatorStack.pop() + " "; | |
o2 = operatorStack[operatorStack.length - 1]; | |
} | |
operatorStack.push(o1); | |
} else if(token === "(") { | |
operatorStack.push(token); | |
} else if(token === ")") { | |
while(operatorStack[operatorStack.length - 1] !== "(") { | |
outputQueue += operatorStack.pop() + " "; | |
} | |
operatorStack.pop(); | |
} | |
} | |
while(operatorStack.length > 0) { | |
outputQueue += operatorStack.pop() + " "; | |
} | |
return outputQueue; | |
} | |
} |
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var ms = new MathSolver(); | |
console.log(ms.infixToPostfix("5 + 3 * 6 - ( 5 / 3 ) + 7")); |
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