C String – strupr() function

strupr() function in C String converts all the characters present in a given string to Uppercase.

The strupr() function is defined in the header file string.h.

It takes a single argument that is the name of the string and is written as follows.

strupr(string_name);

C Program for strupr() function

#include <stdio.h>
#include <string.h>

int main() 
{
  char str[20] = "SimplE2code.Com";
  
  printf("Original String: %s", str);  
  printf("Uppercase Characters: %s", strupr(str));  
 
  return 0;
}

Output:

Original String: SimplE2code.Com
Uppercase Characters: SIMPLE2CODE.COM

Don’t be alarmed if it does not run on your compiler. It is just that some functions like strupr(), which are only available in ANSI C (Turbo C/C++) and are not available in the standard C-GCC compiler.