c++ map获取值
时间: 2023-09-07 08:13:28 浏览: 99
要从C++的map中获取值,你可以使用map的find()函数来查找指定的键,并返回对应的迭代器。迭代器指向map中键值对的位置,通过迭代器可以访问到对应的值。在C++中,迭代器类似于指针,可以使用*运算符来获取迭代器指向的值。
以下是获取map值的示例代码:
```
#include <iostream>
#include <map>
int main() {
std::map<char, int> mymap;
mymap['a'] = 100;
mymap['b'] = 200; mymap['c'] = 300;
std::map<char, int>::iterator it = mymap.find('c');
if (it != mymap.end()) {
std::cout << "Value: " << it->second << std::endl;
} else {
std::cout << "Key not found." << std::endl;
}
return 0;
}
```
在上面的代码中,我们定义了一个map对象mymap,并插入了几个键值对。然后,我们使用find()函数查找键为'c'的值,并将返回的迭代器存储在it中。如果找到了对应的键,我们使用it->second来获取值并输出。如果没有找到键,则输出"Key not found."。
注意,在使用find()函数查找键时,需要判断返回的迭代器是否等于map的end()迭代器,来确定是否找到了对应的键。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
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