Code

#include <stdio.h>
#include <string.h>

int main()
{
    char s[101];
    int i;
    gets(s);
    int len = strlen(s);
    for(i=0; i<len; i++)
    {
        if(s[i] >= 'a' && s[i] <= 'z')
            s[i] -= 32;
        else if(s[i] >= 'A' && s[i] <= 'Z')
            s[i] += 32;
        else if(s[i] >= '0' && s[i] <= '9')
            s[i] = 105 - s[i];
    }
    for(i=len-1; i>=0; i--)
        printf("%c",s[i]);
    printf("\n");
    return 0;
}