STL中string的基本用法范例

#include <iostream>

#include <string>

using namespace std;

//string转char*

void s_c()

{

string str="hello word";

const char* cstr = str.c_str();

cout<<cstr<<endl;

}

//char* 转string

void c_s()

{

char* c = "hello word";

string s(c);

cout<<s<<endl;

}

//string 赋值操作

void string_some()

{

//创建一个空的字符串

string str="hello word";

//使用str 初始化str2

string str2(str);

//使用char*初始化string；

const char* c= "hello word";

string str3(c);

cout<<"str3="<<str3<<endl;

//字符赋值给当前字符串

char s_si[]="2";

string str4(s_si);

cout<<"str4="<<str4<<endl;

//使用n个字符初始化c

int n_i = 5;

char n_c[] = "s";

string str5(n_i,*n_c);

cout<<"str5="<<str5<<endl;

//将s从start开始n个字符赋值给字符串

string s ="ABCDEFG";

int start = 2;

int n =6;

string str6(s,start,n);

cout<<"str6="<<str6<<endl;

//string 通过[],at方式取字符 at方式取字符如果越界可以被异常捕获

string str7="1234567";

str[1];

str.at(1);

}

//string 拼接操作

void string_pin()

{

//+=拼接字符串

string str = "12345";

string str2 = "67890";

str += str2;

cout<<"str="<<str<<endl;

//+=拼接char*

char * c="1234";

string str3="5678";

str3+=c;

cout<<"str3="<<str3<<endl;

//+=拼接char字符

char c_s[]="cd";

string str4 = "ab";

str4+=c_s;

cout<<"str4="<<str4<<endl;

//连接string到当前字符串尾部

string str5="123";

str4.append(str5);

cout<<"str4="<<str4<<endl;

//连接char*到当前字符串尾部

const char* c_s1="cdefg";

str5.append(c_s1);

cout<<"str5="<<str5<<endl;

//连接char 到当前字符串尾部

const char c_s2[]="0987";

string str6="5432";

str6.append(c_s2);

cout<<"str6"<<str6<<endl;

//吧str7中p开始的n个字符串链接到当前字符串尾部

string str7 = "abcdef";

int p=0;int n =2;

str4.append(str7,p,n);

cout<<"str4="<<str4<<endl;

//在当前字符串结尾添加n个字符串a

char c_8[] = "1234";

int n_8 = 2;

string str8 = "asd";

str8.append(n_8,*c_8);

cout<<"str8="<<str8<<endl;

}

//string 查找和替换

void string_find()

{

//find 从n开始查找s所在的位置

string str = "1234567890acsdefgh";

string s = "6";

int n = 4;

int f_s = str.find(s,n);

cout<<"f_s="<<f_s<<endl;

//char*类型同上

const char* s_2 = "7";

int n_2 =2;

int f_s1=str.find(s_2,n_2);

cout<<"f_s1="<<f_s1<<endl;

//

string s_3="e";

int n_3=13;

int n_3_2 = 8;

int f_s2 = str.find(s_2,8,n_3_2);

cout<<"f_s2="<<f_s2<<endl;

//rfind 从后向前查

string s_r = "3";

int f_r = str.rfind(s_r,n);

cout<<"f_r="<<f_r<<endl;

}

//string比较操作

//compare 大于时返回1 小于时返回-1，等于时返回0，比较时参考字典顺序

void str_compare()

{

//string 比较

string s="1";

string c="1";

int comp = s.compare(c);

cout<<"comp="<<comp<<endl;

//char* 比较

const char* c_c="2";

int c_s_comp = s.compare(c_c);

cout<<"c_s_comp="<<c_s_comp<<endl;

//copy子串

string str ="1234567890";

int sr_c = 5;

int po_c = 3;

string so_str = str.substr(sr_c,po_c);

cout<<"so_str="<<so_str<<endl;

}

//string 插入和删除

void de_str()

{

//取str中第五个以后的字符插入到str_num中

string str = "abcdefgh";

string str_num = "123456789";

int num = 5;

string s = str.insert(num,str_num);

cout<<"str="<<s<<endl;

//删除从第pos位置开始的pos_n个元素

int pos = 3;

int pos_n = 2;

s.erase(pos,pos_n);

cout<<"str="<<s<<endl;

}

int main()

{

s_c();

c_s();

string_some();

string_pin();

string_find();

str_compare();

de_str();

cout << ".............." << endl;

return 0;

}