std:string 用法

#include "stdafx.h"

#include <string>

using namespace std;

int main(int argc, char* argv[])

{

 printf("Hello World!\n");

 string s1="hello world!";

 printf("s1.find('o')=%d \n",s1.find('o'));

 printf("s1.find('o',5)=%d \n",s1.find('o',5));
    printf("%s\n",s1.append("Good!").c_str());
 printf("%s \n",s1.substr(2,5).c_str());

 return 0;

}
Hello World!

s1.find('o')=4

s1.find('o',5)=7

hello world!Good!

llo w


#include <cctype>

 #include <algorithm>

//大小写转换

string s = "Clare";

 // toUpper

transform(s.begin(), s.end(), s.begin(), toupper);
 // toLower

 //transform(s.begin(),s.end(),s.begin(),tolower);