WAP to input a character and a string. Each occurrence of a character in the string should be converted to opposite case i.e. upper to lower case or vice versa.

CODE ::

#include <stdio.h>
int main ()
{
    char a[100],c;
    int i,j;
    printf("Enter string: ");
    gets(a);
    fflush (stdin);
    printf("Enter a character which one you want to change: ");
    scanf("%c",&c);
    for(i=0;i<a[i];i++)
    {
        if(a[i]==c)
        {
            if(a[i]>='A'&&a[i]<='Z')
                a[i]=a[i]-'A'+'a';

            else if (a[i]>='a'&&a[i]<='z')
                a[i]=a[i]-'a'+'A';
        }
        printf("%c",a[i]);
    }
    return 0;
}