< cpp‎ | string‎ | byte
Defined in header <cctype>
int toupper( int ch );

Converts the given character to uppercase according to the character conversion rules defined by the currently installed C locale.

In the default "C" locale, the following lowercase letters abcdefghijklmnopqrstuvwxyz are replaced with respective uppercase letters ABCDEFGHIJKLMNOPQRSTUVWXYZ.


ch - character to be converted. If the value of ch is not representable as unsigned char and does not equal EOF, the behavior is undefined.

Return value

Converted character or ch if no uppercase version is defined by the current C locale.


#include <iostream>
#include <cctype>
#include <clocale>
int main()
    unsigned char c = '\xb8'; // the character ž in ISO-8859-15
                              // but ¸ (cedilla) in ISO-8859-1 
    std::setlocale(LC_ALL, "en_US.iso88591");
    std::cout << std::hex << std::showbase;
    std::cout << "in iso8859-1, toupper('0xb8') gives " << std::toupper(c) << '\n';
    std::setlocale(LC_ALL, "en_US.iso885915");
    std::cout << "in iso8859-15, toupper('0xb8') gives " << std::toupper(c) << '\n';


in iso8859-1, toupper('0xb8') gives 0xb8
in iso8859-15, toupper('0xb8') gives 0xb4

See also

converts a character to lowercase
converts a character to uppercase using the ctype facet of a locale
(function template)
converts a wide character to uppercase
C documentation for toupper