C program to convert lower-case letters to upper-case

/* Write a function that will scan a character string passed as an argument and convert all lower-case character into their upper-case equivalent.*/

#include"stdio.h"

void upper(char str1[]);

void main()

{

char str[50], i;

printf("Enter a string: ");

scanf("%[^\n]", str);

upper(str);

printf("\n");

}

void upper(char str1[])

{

int i;

for(i=0; str1[i] != '\0'; i++)

{

str1[i] = toupper(str1[i]);

}

printf("%s", str1);

}

Output: