Namespaces
Variants

std::basic_string<CharT,Traits,Allocator>:: pop_back

From cppreference.net
C++
Strings library
std::basic_string
void pop_back ( ) ;
(constexpr since C++20)

Removes the last character from the string.

Equivalent to erase ( end ( ) - 1 ) .

If empty() is true , the behavior is undefined.

(until C++26)

If empty() is true :

  • If the implementation is hardened , a contract violation occurs. Moreover, if the contract-violation handler returns under “observe” evaluation semantic, the behavior is undefined.
  • If the implementation is not hardened, the behavior is undefined.
(since C++26)

Contents

Complexity

Constant.

Exceptions

Throws nothing.

Notes

In libstdc++, pop_back() is not available in C++98 mode.

Example

Run this code 
#include <cassert>
#include <iomanip>
#include <iostream>
#include <string>
int main()
{
    std::string str("Short string!");
    std::cout << "Before: " << std::quoted(str) << '\n';
    assert(str.size() == 13);
    str.pop_back();
    std::cout << "After:  " << std::quoted(str) << '\n';
    assert(str.size() == 12);
    str.clear();
//  str.pop_back(); // undefined behavior
}

Output: 

Before: "Short string!"
After:  "Short string"

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 534 C++98 std::basic_string did not have the member function pop_back() added

See also

appends a character to the end
(public member function)
removes characters
(public member function)