C++如何遍历map容器_C++ map迭代器与auto关键字遍历方法

#include <iostream>
#include <map>
using namespace std;

int main() {
    map<string, int> scores = {{"Alice", 95}, {"Bob", 87}, {"Charlie", 92}};

    // 使用普通迭代器遍历
    for (map<string, int>::iterator it = scores.begin(); it != scores.end(); ++it) {
        cout << "Key: " << it->first << ", Value: " << it->second << endl;
    }

    return 0;
}

for (map<string, int>::const_iterator it = scores.cbegin(); it != scores.cend(); ++it) {
    cout << it->first << ": " << it->second << endl;
}

// 使用 auto 声明迭代器
for (auto it = scores.begin(); it != scores.end(); ++it) {
    cout << it->first << " -> " << it->second << endl;
}

// 范围 for 循环遍历 map
for (const auto& pair : scores) {
    cout << pair.first << ": " << pair.second << endl;
}

// 修改 map 中的 value
for (auto& pair : scores) {
    pair.second += 5;  // 加分操作
    cout << pair.first << "'s new score: " << pair.second << endl;
}