codegolf - make a number expression - validator

validator.js

var fs = require("fs");

var input = fs.readFileSync("input.txt", "ascii");
var output = fs.readFileSync("output.txt", "ascii");

input = input.split("\n");
output = output.split("\n");

var OK = 0;
for(var i in output) {
	console.log("Case " + (+i+1) + " : " + input[i] + " => " + output[i]);

	var I = parseInt(input[i], 10);
	var O = output[i];

	var stack = [];

	for(var j = 0 ; j < O.length ; j++) {
		var ch = O[j];
		var cc = O.charCodeAt(j);

		if(cc >= 50 && cc <= 57) stack.push(cc - 48);

		else if(ch == "+") {
			stack.push(stack.pop() + stack.pop());
		}

		else if(ch == "-") {
			var n1 = stack.pop();
			var n2 = stack.pop();
			stack.push(n2 - n1);
		}

		else if(ch == "*") {
			stack.push(stack.pop() * stack.pop());
		}

		else if(ch == "/") {
			var n1 = stack.pop();
			var n2 = stack.pop();
			stack.push(Math.floor(n2 / n1));
		}

		else if(ch == ">") {
			var n = stack.pop();
			stack.push(n, n);
		}
	}

	if(stack[0] == I) {
		console.log(" - OK");
		OK++;
	}
	else console.log(" - :(");
}

console.log("Test Result : " + OK + "/" + output.length);