C isupper() function

C isupper(int ch)

The isupper() function is used to check whether a character is an uppercase alphabet (A-Z) or not. The function is defined in the ctype.h header file.

Note: Letter case is the distinction between the letters that are in larger uppercase or capitals (or more formally majuscule) and smaller lowercase (or more formally minuscule) in the written representation of certain languages.

Syntax:

int isupper(int argument);

isupper() Parameters:

Return value from isupper()

• The isupper() function returns non-zero if ch is an uppercase letter; otherwise returns 0.

Example: C isupper() function

#include <stdio.h>
#include <ctype.h>
int main()
{
   char ch;
   ch = 'R';
   printf("\nIf %c is  isupper(?: %d", ch, isupper(ch));
   ch = 'a';
   printf("\nIf %c is  isupper(?: %d", ch, isupper(ch));
   ch = 'P';
   printf("\nIf %c is  isupper(?: %d", ch, isupper(ch));
   ch = '+';
   printf("\nIf %c is  isupper(?: %d", ch, isupper(ch));     
   return 0;
}

Output:

If R is  isupper(?: 1
If a is  isupper(?: 0
If P is  isupper(?: 1
If + is  isupper(?: 0

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