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isupper

From cppreference.com
< c‎ | string‎ | byte
Defined in header <ctype.h>
int isupper( int ch );

Checks if the given character is an uppercase character according to the current C locale. In the default "C" locale, isupper returns true only for the uppercase letters (ABCDEFGHIJKLMNOPQRSTUVWXYZ).

If isupper returns true, it is guaranteed that iscntrl, isdigit, ispunct, and isspace return false for the same character in the same C locale.

The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF.

Contents

[edit] Parameters

ch - character to classify

[edit] Return value

Non-zero value if the character is an uppercase letter, zero otherwise.


[edit] Example

#include <stdio.h>
#include <ctype.h>
#include <locale.h>
 
int main(void)
{
    unsigned char c = '\xc6'; // letter Æ in ISO-8859-1
    printf("In the default C locale, \\xc6 is %suppercase\n",
           isupper(c) ? "" : "not " );
    setlocale(LC_ALL, "en_GB.iso88591");
    printf("In ISO-8859-1 locale, \\xc6 is %suppercase\n",
           isupper(c) ? "" : "not " );
}

Output:

In the default C locale, \xc6 is not uppercase
In ISO-8859-1 locale, \xc6 is uppercase

[edit] References

  • C11 standard (ISO/IEC 9899:2011):
  • 7.4.1.11 The isupper function (p: 203)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.4.1.11 The isupper function (p: 184)
  • C89/C90 standard (ISO/IEC 9899:1990):
  • 4.3.1.10 The isupper function

[edit] See also

checks if a wide character is an uppercase character
(function) [edit]
C++ documentation for isupper
ASCII values
(hex)
characters

iscntrl
iswcntrl

isprint
iswprint

isspace
iswspace

isblank
iswblank

isgraph
iswgraph

ispunct
iswpunct

isalnum
iswalnum

isalpha
iswalpha

isupper
iswupper

islower
iswlower

isdigit
iswdigit

isxdigit
iswxdigit

0 - 8 0x00-0x08 control codes (NUL, etc.) ≠0 0 0 0 0 0 0 0 0 0 0 0
9 0x09 tab (\t) ≠0 0 ≠0 ≠0 0 0 0 0 0 0 0 0
10 - 13 0x0A-0x0D whitespaces (\n,\v,\f,\r) ≠0 0 ≠0 0 0 0 0 0 0 0 0 0
14 - 31 0x0E-0x1F control codes ≠0 0 0 0 0 0 0 0 0 0 0 0
32 0x20 space 0 ≠0 ≠0 ≠0 0 0 0 0 0 0 0 0
33 - 47 0x21-0x2F !"#$%&'()*+,-./ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
48 - 57 0x30-0x39 0123456789 0 ≠0 0 0 ≠0 0 ≠0 0 0 0 ≠0 ≠0
58 - 64 0x3a-0x40 :;<=>?@ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
65 - 70 0x41-0x46 ABCDEF 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 ≠0
71 - 90 0x47-0x5A GHIJKLMNOPQRSTUVWXYZ 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 0
91 - 96 0x5B-0x60 [\]^_` 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
97 -102 0x61-0x66 abcdef 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 ≠0
103-122 0x67-0x7A ghijklmnopqrstuvwxyz 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 0
123-126 0x7B-0x7E {|}~ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
127 0x7F backspace character (DEL) ≠0 0 0 0 0 0 0 0 0 0 0 0