[C++] string

string

table list

• 字符串的大小写
• string char[] (visual studio)
• string int

someting else basic function

init

string test1;    //空串

string test2 = "内容"; //赋值=

string test3("内容");   //使用引用字符数组作为参数传给构造函数

string test4(test2); //用一个string初始化另一而string

string test5(test2,pos,num); //从test2中的第pos个位置开始，拷贝个数为num个字符

string test6 = test2 + "内容" + test3 //混合初始化

string test7 = test2.substr(pos,num); //从test2中的第pos个位置开始，拷贝个数为num个字符

string test8 = test2.substr(); //参数列表为空则会拷贝test2的整个对象（复制test2的简便方法）

string test9(num,ch); //拷贝num个字符型ch到test9

std::basic_string::find

#include <string>
#include <iostream>
 
void print(std::string::size_type n, std::string const &s)
{
    if (n == std::string::npos) {
        std::cout << "not found
";
    } else {
        std::cout << "found: " << s.substr(n) << '
';
    }
}
 
int main()
{
    std::string::size_type n;
    std::string const s = "This is a string";
 
    // search from beginning of string
    n = s.find("is");
    print(n, s);
 
    // search from position 5
    n = s.find("is", 5);
    print(n, s);
 
    // find a single character
    n = s.find('a');
    print(n, s);
 
    // find a single character
    n = s.find('q');
    print(n, s);
}

found: is is a string
found: is a string
found: a string
not found