即使它不应该使用Printf [英] Printf even though it shouldn't

问题描述

我具有if语句的这一部分，并且得到了一个奇怪的输出.

I have this part of an if statement and I'm getting a weird output.

int x = 10;

if(1 < x < 5){
    printf("F\n");
}

为什么打印"F"?逻辑上说if语句不是假的，因为x大于1但不小于5吗?

Why does it print "F"? Logically isn't the if statement false because x is greater than 1 but not less than 5?

推荐答案

在C语言中，您不能像这样链接比较.表达式 1<x ＜5 被评估为(1< x)<5 :因此对于 x = 10 ，表达式为(1< 10)<5 .(1< 10)为true，C表示值为 1 ，因此表达式简化为 1<5 .这始终是正确的，并且您的printf()如果已执行.

In C, you can't chain comparisons like that. The expression 1 < x < 5 is evaluated as (1 < x) < 5: so for x = 10, the expression is (1 < 10) < 5. (1 < 10) is true, which C represents as the value 1, so the expression reduces to 1 < 5. This is always true, and your printf() if executed.

正如级别999999所说，在C语言中，您需要显式地将单个比较与&& 和 || 组合.

As level-999999 says, in C you need to explicitly combine single comparisons with && and ||.

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