javascript - 无法输入IF语句

Question

我正在尝试解决 Javascript 中最大回文积的欧拉项目问题，但我不明白为什么程序不输入 IF 语句 if (number.toString() == number. toString().split('').reverse().join('')):

(function palyndrom(max, min) {
    
    top: 
    for (i = max; i > min; i--) {
        for (c = max; c > min; c--) {
            if(i*c == c*i) {
                alert('same was before');
            }
            
            else {
                var number = i*c;
                console.log('i*c = ' + i + '*' + c + ' = ' + number); 
    
//this if not entered, alert doesn't work
                if (number.toString() == number.toString().split('').reverse().join('')) {
                    alert('PALYNDROM FOUND: i*c = ' + i + '*' + c + ' = ' + number);
                    break top;
                }   
            }
        }
    }
})(999, 900);

Answer 1

i*c == c*i

结果总是 true。该函数永远不会到达 else 部分。我想你想做的是

i === c

相反:

(function palyndrom(max, min) {
top:
    for (var i = max; i > min; i--) {
        for (var c = max; c > min; c--) {
            if (i === c) {
                alert('same was before');
            } else {
                var number = i * c;
                console.log('i*c = ' + i + '*' + c + ' = ' + number);

                if (number.toString() == number.toString().split('').reverse().join('')) {
                    alert('PALYNDROM FOUND: i*c = ' + i + '*' + c + ' = ' + number);
                    break top;
                }
            }
        }

    }
} )(999, 900);