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

void push_back( CharT ch );

(constexpr since C++20)

Appends the given character ch to the end of the string.

Parameters

the character to append

Return value

(none)

Complexity

Amortized constant.

Exceptions

If the operation would cause size() to exceed max_size(), throws std::length_error.

If an exception is thrown for any reason, this function has no effect (strong exception safety guarantee).

Example

#include <iomanip>
#include <iostream>
#include <string>

int main()
{
    std::string str{"Short string"};
    std::cout << "1) " << std::quoted(str) << ", size: " << str.size() << '\n';
    
    str.push_back('!');
    std::cout << "2) " << std::quoted(str) << ", size: " << str.size() << '\n';
}

Output:

1) "Short string", size: 12
2) "Short string!", size: 13

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 7	C++98	1) the description was missing in the C++ standard 2) the parameter type was constCharT	1) description added 2) changed to `CharT`
LWG 847	C++98	there was no exception safety guarantee	added strong exception safety guarantee