Introduction to the usage of string in c++

string is included in the string library (not string.h, not .h). It can define a string variable just like defining a character, and the powerful C also has various built-in Function, the basic implementation eliminates the need to hand-write functions, and can also perform lexicographic comparisons and string operations.

1. Bitwise and string operations

For example

string s = "abcdef";
cout << s[0] << endl;

The result should be the output character 'a', and the string type can also be used Directly add another string, for example

string a = "abc", b = "bcd";
a = a + b;
cout << a << endl;

The result should be the output string "abcbcd".

2. Built-in functions

The string type actually includes many functions, such as

string s = "a";
    s.append(2,'b');//s.append(n,c);在s串后面加入n个c字符（append还有其他用法，详情可百度）
    s.erase(s.begin(),s.begin()+2);//s.erase(l,r);删除某个区间，l,r都为迭代器
    s.erase(it);//删除一个字符，it为迭代器
    s.size();//返回字符串s的长度大小
    s.begin();//返回首位置的迭代器
    s.end();//返回末位置的迭代器
    s.insert(it,ch);//在it位置插入ch字符，it为迭代器
    s.resize(len,c);//把字符串当前大小置为len，并用c填充不足的部分
    s.empty();//判断是否为空串
    s.length();//返回字符串的长度
    s.max_size();//返回当前系统string对象可存放的最大长度
    s.capacity();//返回当前容量
    s.at(k);//返回第k+1个字符（该用法会坚持是否越界）
    s.c_str();//返回C字符串的指针，内容为s串
    s.find(s1);//查找s中是否包含s1，并返回头位置，找不到则返回string::npos
    s.replace(k,x,ch);//从k位置开始，把后面的x个元素替换为ch（还有很多其他用法）
    s.swap(s2);//交换两个string字符串

and string also supports direct comparison of two strings. size (built-in lexicographic comparison).

Of course, in addition to the functions written above, string has many other functions.

Recommended tutorial: c tutorial

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