如果语句在JS中执行时甚至为false [英] If statement executes even when false in JS

问题描述

即使if语句为false，java脚本中的Two-sum程序也会运行。当我在textbox1中输入一系列数字时，在textbox2中输入一个数字。它应该显示来自textbox1的2个数字，等于textbox2。



例如1,2,3,6 in textbox1。



5 in textbox2。



答案应该是2,3。

The Two-sum program in java script runs even when the if statement is false. When I enter a series of number in textbox1, and one number in textbox2. It should display 2 numbers from textbox1 which equals to textbox2.

For eg 1,2,3,6 in textbox1.

5 in textbox2.

The answer should be 2,3.

function TwoSum() {
    inputArray1 = document.getElementById("inputText1").value.split(",");
    inputArray2 = document.getElementById("inputText2").value.split(",");

    var two = [];
    var sum = 0;
    var y = 0;
    y = inputArray2[0];
    var z = 0; 
    var a = 0; //input array 1
    var b = 0; //input array 2

    for (i = 0; i < inputArray1.length - 1; i++) {
        if (z == 0) {
            for (j = inputArray1.length - 1; j >= i; j--) {
                //if (inputArray1[i] + inputArray1[j] == y)
                a = inputArray1[i];
                b = inputArray1[j];

                if (a + b == y)
                {

                    two[sum] = inputArray1[i];
                    sum++;
                    two[sum] = inputArray1[j];
                    sum++;
                    z++;
                    break;
                }
            }
        }
        if (z > 0)
            break;
        else
            var incorrect = false;
    }

    if (z > 0)
        document.getElementById("result").value = two.join(",");
    else
        document.getElementById("result").value = incorrect;
}

我的尝试：



当我在1个textBox中输入2,4,5,3而在第2个文本框中输入5时，答案应该在第一个循环中打印2,3。但是当我调试时，if（a + b == y）没有被执行。它无论如何都会读为false并跳回到= inputArray1 [i]，b = inputArray2 [i]。

What I have tried:

When I enter 2,4,5,3 in 1 textBox and 5 in 2nd textbox, the answer should print 2,3 in the first loop itself. But when I debug, the if(a+b==y) isn't getting executed. It reads as false no matter what and jumps back to a=inputArray1[i], b= inputArray2[i].

推荐答案

因为所有数字都在字符串中格式。因此2 + 3实际上被评估为字符串23，而不是算术和5.您首先需要将字符转换为实际数值。请参阅 JavaScript parseInt（）函数 [ ^ ]。

Because all your numbers are in character string format. So 2 + 3 is actually evaluated as the string 23, not the arithmetic sum 5. You first need to convert your characters into actual numeric values. See JavaScript parseInt() Function[^].

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