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问题描述
通过 aMap [key] 和 aMap.at(key)获取值有何区别? C ++?
What is the difference in getting a value through aMap[key] and aMap.at(key) in C++?
推荐答案在C ++ 11中 map :: at exists (谁知道?)。
In C++11 map::at exists (who knew?).
如果键不存在则抛出异常, find 返回 aMap.end()如果元素不存在, operator [] value-initializes 如果没有值,则为相应键的新值。
It throws an exception if the key doesn't exist, find returns aMap.end() if the element doesn't exist, and operator[] value-initializes a new value for the corresponding key if no value exists there.
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C ++中map []和map.at之间的区别?
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