处理string对象中的字符c++primer 81

#include<iostream>

using namespace std;

#include<string>

int main()

{

 //处理每个字符，范围for

string s1 = "aigjiouarjiu";

for (auto c : s1)

{

int i = 1;

cout<<"s1字符串的第"<<i<<"个字符："<<c<<endl;

}

string s2 = "sg,gg.gga,,,,!!!!rgq/q/gq'qgr???";

decltype (s2.size()) punt=0;  //decltype (s1.size(),返回一个数据类型

for (auto c : s2)

{

if (ispunct(c))

{

punt++;

}

}

cout << "s2中有" << punt << "个标点符号" << endl;

//使用范围for改变字符串的值，声明部分为引用

string s3 = "huang jun mu";

for (auto &c : s3)

{

c = toupper(c);

}

cout << "s3:" << s3 << endl;

//只处理一部分字符

//下标运算符

string s4 = "huang junmu";

if (!s4.empty())

{

s4[0] = toupper(s4[0]);

}

cout << "s4: " << s4 << endl;

//使用下标进行迭代

for (decltype(s4.size()) index = 0; index != s4.size() && !isspace(s4[index]); ++index)

{

s4[index] = toupper(s4[index]);

}

cout << "s4: " << s4 << endl;

//使用下标执行随机访问

system("pause");

}