尝试获取用户输入并输出一条消息，期望当我输入一个有效名称时它会输出所有这些信息

Question

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int main() {

    string gun = "";
    cout << "Enter The Gun You Would Like To Know The Type Of Ammo For: \n";
    getline(cin, gun);
    if (gun == "b95" || "B95" || "windchester" || "wind chester" || "Windchester" || "Wind Chester" || "longhorn" || "Long Horn" || "fal" || "FAL")
    {
        cout << "The Type Of Ammo For The " << gun << " Is 308 Windchester";
    }   
    if (gun == "izh rifle" || "IZH Rifle" || "izhrifle" || "izh rifle" || "sks" || "SKS" || "akm" || "AKM")
    {
        cout << "The Type Of Ammo For The " << gun << " 7.62x39mm";
    }
    if (gun == "Mangnum" || "mangnum" || "Repetor" || "repetor")
    {
        cout << "The Type Of Ammo For The " << gun << ".357";
    }
    return 0;
}

当程序是运行例如，我会输入 sks，它会输出所有 cout 消息，例如：The Type Of Ammo For The sks Is 308 WindchesterThe Type Of Ammo For The sks 7.62x39mmThe sks.357

的弹药类型

Answer 1

如果这样的条件不行。如果你想要这个，你必须这样写：

 if (gun == "izh rifle" || gun ==  "IZH Rifle" || gun == "izhrifle" || gun ==  "izh rifle" || 
   gun ==  "sks" ||gun ==  "SKS" ||gun ==  "akm" ||gun ==  "AKM")

基本上正确的比较需要比较两个值，而不是一个。

Answer 2

你不能在 C++ 中编写这样的布尔表达式。布尔表达式的每一面都是布尔值，所以在您的情况下，所有三个 if 始终为真，因为非空字符串在布尔表达式中为真。请阅读布尔表达式并写下类似的东西如果（输入== "str1" || 输入== "str2" 等）

尝试获取用户输入并输出一条消息，期望当我输入一个有效名称时它会输出所有这些信息

Trying to get user input and cout a message expect when I enter a valid name it couts all of them

c++

stringstream