您可以在 if 语句中使用 2 个或更多 OR 条件吗?

2022-01-20 00:00:00 conditional-statements c++

在论坛上提问之前，我尝试过自己测试，但我测试它的简单代码似乎不起作用.

I tried to test this myself before asking on the forum but my simple code to test this didn't seem to work. 

#include <iostream>
using namespace std;

int main() {
cout << "Enter int: ";
int number;
cin >> number;
if (number==1||2||3) {
    cout << "Your number was 1, 2, or 3." << endl;
}
else if (number==4||5||6) {
    cout << "Your number was 4, 5, or 6." << endl;
}
else {
    cout << "Your number was above 6." << endl;
}
return 0;
}

它总是返回第一个条件.我的问题是，是否有可能有超过 2 个 OR 条件?还是我的语法不正确?

It always returns the first condition. My question is, is it even possible to have more than 2 OR conditions? Or is my syntax incorrect?

推荐答案

您需要以不同的方式编写测试代码:

You need to code your tests differently:

if (number==1 || number==2 || number==3) {
    cout << "Your number was 1, 2, or 3." << endl;
}
else if (number==4 || number==5 || number==6) {
    cout << "Your number was 4, 5, or 6." << endl;
}
else {
    cout << "Your number was above 6." << endl;
}

你这样做的方式，第一个条件被解释为好像是这样写的

The way you were doing it, the first condition was being interpreted as if it were written like this

if ( (number == 1) || 2 || 3 ) {

逻辑或运算符 (||) 被定义为在左侧为真或左侧为假而右侧为真时评估为真值.由于 2 是真值(3 也是如此)，因此无论 number 的值如何，表达式都会计算为真.

The logical or operator (||) is defined to evaluate to a true value if the left side is true or if the left side is false and the right side is true. Since 2 is a true value (as is 3), the expression evaluates to true regardless of the value of number.

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