Difference between revisions of "cpp/string/basic string/pop back"
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< cpp | string | basic string
(Added LWG issue #534 DR (part 3/3).) |
(Added a note about the libstdc++ conformance of LWG 534.) |
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===Exceptions=== | ===Exceptions=== | ||
Throws nothing. | Throws nothing. | ||
| + | |||
| + | ===Notes=== | ||
| + | In libstdc++, {{tt|pop_back()}} is [https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.shrink not available] in C++98 mode. | ||
===Example=== | ===Example=== | ||
Revision as of 01:22, 31 May 2023
void pop_back(); |
(until C++20) | |
| constexpr void pop_back(); |
(since C++20) | |
Removes the last character from the string.
Equivalent to erase(end() - 1). The behavior is undefined if the string is empty.
Contents |
Parameters
(none)
Return value
(none)
Complexity
Constant.
Exceptions
Throws nothing.
Notes
In libstdc++, pop_back() is not available in C++98 mode.
Example
Run this code
#include <cassert> #include <string> #include <iomanip> #include <iostream> 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) |
