<分区>
在 http://www.cplusplus.com/reference/map/map/begin/ 的示例中
// map::begin/end
#include <iostream>
#include <map>
int main ()
{
std::map<char,int> mymap;
std::map<char,int>::iterator it;
mymap['b'] = 100;
mymap['a'] = 200;
mymap['c'] = 300;
// show content:
for (std::map<char,int>::iterator it=mymap.begin(); it!=mymap.end(); ++it)
std::cout << it->first << " => " << it->second << '\n';
return 0;
}
为什么在 for 循环中迭代器 it 是预递增的?