The toupper() function defined in the ctype.h header file. It helps to convert the given lowercase character into an uppercase character.
int toupper(int argument); #where argument will be a character
The toupper() function takes a single parameter and is in the form of an integer. When a character is passed it is converted into the integer value corresponding to its ASCII value.
Parameter | Description | Required / Optional |
---|---|---|
argument | The character needs to be converted | Required |
This function converts the given lowercase character to an uppercase character. The value is returned as an int value that can be implicitly cast to char. If the passed argument is not a lowercase letter it will return the same passed character.
Input | Return Value |
---|---|
lowercase character | corresponding uppercase character |
uppercase character or a non-alphabetic character | the character itself |
#include <stdio.h>
#include <ctype.h>
int main()
{
char ch, output;
ch = 'A';
output = toupper(ch);
printf("toupper(%c) = %c\n", ch, output);
ch = 'a';
output = toupper(ch);
printf("toupper(%c) = %c\n", ch, output);
ch = '+';
output = toupper(ch);
printf("toupper(%c) = %c\n", ch, output);
return 0;
}
Output:
toupper(A) = A toupper(a) = A toupper(+) = +
#include <stdio.h>
#include <ctype.h>
int main () {
int k = 0;
char ch;
char st[] = "programming";
while( st[k]) {
putchar(toupper(st[k]));
k++;
}
return(0);
}
Output:
PROGRAMMING