C++ 将一个字符串的索引与另一个字符串进行比较? [英] C++ comparing the index of a string to another string?

问题描述

如何比较字符串中的单个字符和另一个字符串(可能大于一个字符，也可能不大于一个字符)

How can I compare a single character from a string, and another string (which may or may not be greater than one character)

这个程序给了我将近 300 行的随机错误.错误也没有引用特定的行号，只是很多关于char*"、"或std::to_string"的内容.

This program gives me almost 300 lines of random errors. The errors don't reference a specific line number either, just a lot of stuff about "char* ", "", or "std::to_string".

#include <iostream>
#include <string>

using std::cout;
using std::string;

int main() {
    string str = "MDCXIV";
    string test = "D";

    if (test == str[4]) {     // This line causes the problems
        cout << test << endl;
    }
    return 0;
}

推荐答案

您需要先将 str[4](这是一个字符)转换为字符串，然后才能将其与另一个字符串进行比较.这是一个简单的方法来做到这一点

You need to convert str[4] (which is a char) to a string before you can compare it to another string. Here's a simple way to do this

if (test == string(1, str[4])) {

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