void resize (size_t n); void resize (size_t n, char c);
测试代码：
// resizing string
#include <iostream>
#include <string>
int main ()
{
std::string str ("I like to code in C");
std::cout << str << ‘\n‘;
unsigned sz = str.size();
str.resize (sz+2,‘+‘);
std::cout << str << ‘\n‘;
str.resize (14);
std::cout << str << ‘\n‘;
return 0;
}
原文：http://www.cnblogs.com/icode-girl/p/5365004.html