toupper() function in c programming is used to convert lowercase alphabets to uppercase letters.
When a programmer passed a lowercase alphabet to toupper() function then it converts it to uppercase.
Or when a uppercase alphabet is passed then function returns same value.
Syntax for toupper() function in c :-
int toupper(int ch);
Example Program for toupper() in c :-
Let's go with an simple s example program to convert lower case alphabet to uppercase using toupper() function.
Note :- Remember toupper() in c only takes one character at a time.
So if you want to convert a hole word then use while loop for it