C++之string
#include <iostream>
using namespace std;
/*
string();//创建一个空的字符串
string(const char* s);//使用字符串s初始化
string(const string& str);//使用一个string对象初始化另外一个string对象
string(int n,char c);//使用n个字符c初始化
*/
void test1()
{
string s1;//默认构造
const char *str = "hello woreld!";
string s2(str);
cout << "s2 = "<<s2<<endl;
string s3(s2);
cout << "s3 = "<<s3<<endl;
string s4(5,'b');
cout << "s4 = "<<s4<<endl;
}
int main()
{
test1();
cout << "Hello World!" << endl;
return 0;
}
#include <iostream>
#include<string>
using namespace std;
/*
string& operator=(const char* s);//char*类型字符串 赋值给当前的字符串
string& operator=(const string &s);//把字符串s赋给当前的字符串
string& operator=(char c);//字符赋值给当前的字符串
string& assign(const char *s);//把字符串s赋给当前的字符串
string& assign(const char *s, int n);//把字符串s的前n个字符赋给当前的字符串
string& assign(const string &s);//把字符串s给当前字符串
string& assign(int n, char c);//用n个字符c赋给当前字符串
*/
void test1()
{
string s1 = "hello woreld!";
cout << "s1 = "<<s1<<endl;
string s2(s1);
cout << "s2 = "<<s2<<endl;
string s3 ;
s3 = 'b';
cout << "s3 = "<<s3<<endl;
string s4;
s4.assign("hello woreld!");
cout << "s4 = "<<s4<<endl;
string s5;
s5.assign("hello woreld!",5);
cout << "s5 = "<<s5<<endl;
string s6;
s6.assign(s5);
cout << "s6 = "<<s6<<endl;
string s7;
s7.assign(5,'b');
cout << "s7 = "<<s7<<endl;
}
int main()
{
test1();
cout << "Hello World!" << endl;
return 0;
}
#include <iostream>
#include<string>
using namespace std;
/*
string& operator+=(const char* str);//重载+=操作符
string& operator+=(const char c);//重载+=操作符
string& operator+=(const string& str);//重载+=操作符
string& append(const char *s);//把字符串s连接到当前字符串结尾
string& append(const char *s, int n);//把字符串s的前n个字符连接到当前字符串结尾
string& append(const string &s);//同operator+=(const string& str)
string& append(const string &s，int pos，int n); //字符s中从pos开始的n个字符连接到字符串结尾
*/
void test1()
{
string s1 = "I";
cout << "s1 = "<<s1<<endl;
s1 += " LOVE GAME";
cout << "s1 = "<<s1<<endl;
string s2 = ":";
s1 += s2;
cout << "s1 = "<<s1<<endl;
// s1.append(" LOL DNF");
// s1.append(" LOL DNF",4);
string s3 = " LOL DNF";
//s1.append(s3);
s1.append(s3,0,4);
cout << "s1 = "<<s1<<endl;
}
int main()
{
test1();
cout << "Hello World!" << endl;
return 0;
}
#include <iostream>
#include<string>
using namespace std;
//查找
void test1()
{
string str1 = "abcdefgde";
int pos = str1.find("de");
if(pos == -1)
{
cout<<"no find"<<endl;
}
else
{
cout<<"finded , pos = "<<pos<<endl;
}
//find和rfind的区别
//find:从左往右查找；rfind:从右往左查找
int pos2 = str1.rfind("de");
if(pos2 == -1)
{
cout<<"no find"<<endl;
}
else
{
cout<<"finded , pos = "<<pos2<<endl;
}
}
int main()
{
test1();
cout << "Hello World!" << endl;
return 0;
}
void test2()
{
string str1 = "abcdefgde";
//将bc替换成2222
str1.replace(1,3,"2222");
cout<<str1<<endl;
}
int main()
{
test2();
cout << "Hello World!" << endl;
return 0;
}
#include <iostream>
#include<string>
using namespace std;
//查找
void test1()
{
string str1 = "hello";
string str2 = "xello";
if(str1.compare(str2) == 0)
{
cout<<"str1 = str2"<<endl;
}
else if(str1.compare(str2) > 0)
{
cout<<"str1 > str2"<<endl;
}
else
{
cout<<"str1 < str2"<<endl;
}
}
int main()
{
test1();
cout << "Hello World!" << endl;
return 0;
}
#include <iostream>
#include<string>
using namespace std;
//string字符存取
void test1()
{
string str1 = "hello";
//cout<<"str1 = "<<str1<<endl;
//通过[]访问单个字符
for(unsigned int i = 0;i < str1.size();i++)
{
cout<<str1[i]<<" ";
}
cout<<endl;
//通过at方式访问单个字符
for(unsigned int i = 0;i<str1.size();i++)
{
cout<<str1.at(i)<<" ";
}
cout<<endl;
//通过[]修改单个字符
str1[0] = 'x';
cout<<"str1 = "<<str1<<endl;
//通过at方式修改单个字符
str1.at(1) = 'x';
cout<<"str1 = "<<str1<<endl;
}
int main()
{
test1();
cout << "Hello World!" << endl;
return 0;
}
#include <iostream>
#include<string>
using namespace std;
//string字符插入和删除
void test1()
{
string str1 = "hello";
cout<<"str1 = "<<str1<<endl;
//插入
str1.insert(1,"222");
cout<<"str1 = "<<str1<<endl;
//删除
str1.erase(1,3);
cout<<"str1 = "<<str1<<endl;
}
int main()
{
test1();
cout << "Hello World!" << endl;
return 0;
}
#include <iostream>
#include<string>
using namespace std;
//string字符中求子串
void test1()
{
string str1 = "hello";
cout<<"str1 = "<<str1<<endl;
string subStr = str1.substr(2,2);
cout<<"subStr = "<<subStr<<endl;
}
//使用的例子 获取邮箱的用户名
void test2()
{
string str2 = "zhangsan@sina.com";
int pos = str2.find("@");
string subStr = str2.substr(0,pos);
cout<<"subStr = "<<subStr<<endl;
}
int main()
{
test2();
cout << "Hello World!" << endl;
return 0;
}
