Convert into upper string

Program:

#include<stdio.h>
int main()
{
char s1[30],s2[30];
int i=0;
printf("Enter a string: ");
scanf("%s",s1);
while(s1[i]!='\0')
{
if(s1[i]>=97 && s1[i]<=122)
{
s2[i]=s1[i]-32;
}
else
{
s2[i]=s1[i];
}
i++;
}
    s2[i]='\0';
    printf("Upper case string: %s",s2);
return 0;
}

Output: