C++ 基础笔记

public static member constant

std::string::npos

<string>

static const size_t npos = -1;

Maximum value for size_t

npos is a static member constant value with the greatest possible value for an element of type size_t.

This value, when used as the value for a len (or sublen) parameter in string's member functions, means "until the end of the string".

As a return value, it is usually used to indicate no matches.

This constant is defined with a value of -1, which because size_t is an unsigned integral type, it is the largest possible representable value for this type.

public member function

std::string::erase

<string>

• C++98
• C++11

sequence (1)

 string& erase (size_t pos = 0, size_t len = npos);

character (2)

iterator erase (const_iterator p);

range (3)

iterator erase (const_iterator first, const_iterator last);

Erase characters from string

Erases part of the string, reducing its length:

(1) sequence

Erases the portion of the string value that begins at the character position pos and spans len characters (or until the end of the string, if either the content is too short or if len is string::npos.
Notice that the default argument erases all characters in the string (like member function clear).

(2) character

Erases the character pointed by p.

(3) range

Erases the sequence of characters in the range [first,last).

// string::erase#include <iostream>#include <string>int main (){  std::string str ("This is an example sentence.");  std::cout << str << '\n';                                           // "This is an example sentence."  str.erase (10,8);                        //            ^^^^^^^^  std::cout << str << '\n';                                           // "This is an sentence."  str.erase (str.begin()+9);               //           ^  std::cout << str << '\n';                                           // "This is a sentence."  str.erase (str.begin()+5, str.end()-9);  //       ^^^^^  std::cout << str << '\n';                                           // "This sentence."  return 0;}

simpio.h

GetInteger

Getread

GetLine