增量运算符如何在if语句中工作? [英] How does the increment operator work in an if statement?

问题描述

    #include <stdio.h>

    int main()
    {
        int x = 0;

        if (x++)
            printf("true\n");
        else if (x == 1)
            printf("false\n");
        return 0;
    }

输出:

false

为什么输出错误?

x++是发布增量；这意味着使用x的值，然后将其递增. 如果是这样，则应使用x=0，并且答案应为真.

x++ is post increment; this means that the value of x is used then it is incremented. If it is so, then x=0 should be used and the answer should be true.

推荐答案

在C中，0被视为false.在x++中，在表达式中使用x的值，即0，它变为

In C, 0 is treated as false. In x++, the value of x, i.e, 0 is used in the expression and it becomes

if(0)  // It is false
    printf("true\n");  

if的正文未执行.之后，x现在是1.现在检查else if中的条件，即x == 1.由于x是1，因此此条件的值为true，因此它的主体被执行并打印"false".

The body of if doesn't get executed. After that x is now 1. Now the condition in else if, i.e, x == 1 is checked. since x is 1 , this condition evaluates to true and hence its body gets executed and prints "false".

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