std::string的reserve()和resize()函数的区别

参考：http://blog.csdn.net/freecloud_insky/article/details/47058597

分析以下代码，可见

#include <stdlib.h>
#include <stdio.h>
#include <string>

int main()
{
//1 string内存分配按照:(n*16-1)分配，n好像是次数
std::string str1 = "hello";
str1.reserve(20);

//2
std::string str2 = "hello";
str2.resize(2);

//3
std::string str3 = "hello";
str3.resize(10);

//4
std::string str4 = "hello";
str4.resize(10, 'b');

return 0;
}

进阶，实际应用

/*获取当前路径的父路径*/
string CFileUtils::get_parent_path(const string & path)
{
string file(path);
while (file.data()[file.length() - 1] == '\\' || file.data()[file.length() - 1] == '/')
{
file.resize(file.length() - 1);
}
int size = file.find_last_of('\\');
if (size > 0)
{
file.resize(size + 1);
}
return file;
}