Missing DigitII

MissingDigitII.js

// Missing DigitII


// Using the JavaScript language, have the function MissingDigitII(str) take the str parameter, which will be a simple mathematical formula with three numbers, a single operator (+, -, *, or /) and an equal sign (=) and return the two digits that complete the equation. In two of the numbers in the equation, there will be a single ? character, and your program should determine what digits are missing and return them separated by a space. For example, if str is "38?5 * 3 = 1?595" then your program should output 6 1. 

// The ? character will always appear in both the first number and the last number in the mathematical expression. There will always be a unique solution. 

function MissingDigitII(str) {
  
    str=str.replace(/=/,'===')
    for(i=0;i<10;i++){
        for(j=0;j<10;j++){
            temp=str.replace(/\?/,i)
            temp=temp.replace(/\?/,j)
            if(eval(temp)){
                return i+' '+j
            }
        }
    }
}

//console.log(MissingDigitII("38?5 * 3 = 1?595")); // 6 1
console.log(MissingDigitII("56? * 106 = 5?678")); // 3 9
//console.log(MissingDigitII("18?1 + 9 = 189?")); // 8 0


// solution 2


// function MissingDigitII(str) {
// 	for (let i = 0; i <= 9; i++) {
// 		for (let j = 0; j <= 9; j++) {
// 			let newStr = str.replace(/\?/, String(i)).replace(/\?/, String(j)).replace(/=/, '===');
// 			if (eval(newStr)) {
// 				return `${i} ${j}`;
// 			}
// 		}
// 	}
// }


// solution 3


// function MissingDigitII(str) { 
// 	var slot1 = str.indexOf('?');
// 	var slot2 =  str.lastIndexOf('?');
	

//   for (var i = 0; i <= 9; i++) {
//       for (var j = 0; j <= 9; j++) {
//       	var strArr = str.split('');
//         strArr[slot1] = i;
//         strArr[slot2] = j;
//         strArr = strArr.join('').split(' ');
//         var num1 = Number(strArr[0]);
//         var num2 = Number(strArr[2]);
//         var answer = Number(strArr[4]);
//         var equastion = determineSign(strArr[1], num1, num2);
//         if (equastion === answer)
//           	return [i, j].join(' ');
     
//       }
//   }
  
// 	function determineSign(str, num1, num2) {
// 		if (strArr[1] === '+')
// 			return (num1 + num2);
// 		if (strArr[1] === '-')
// 			return (num1 - num2);
// 		if (strArr[1] === '*')
// 			return (num1 * num2);
// 		if (strArr[1] === '/')
// 			return (num1 / num2);
// 	}
// }