#include <stdio.h>
#define MAXLEN (1000+1)
int charCount(char *, char);
void commonChars(char *, char *);
void ror(char *);
void rol(char *);
char *strCopy(char *, const char *);
int isPrefix(const char *, const char *);
char *substring(char *, const char *);
int main()       // main() of assignment 10
{
    char x[MAXLEN], c, y[MAXLEN], z[MAXLEN], *sP ; 

    printf("Enter the 1st string:\n") ;
    scanf("%[^\n]", x) ;
    printf("Enter a character:\n") ;
    scanf(" %c", &c) ;
    printf("%d occurrence of %c in \"%s\"\n", 
            charCount(x, c), c, x);
    printf("Enter the 2nd string:\n") ;
    scanf(" %[^\n]", y) ;
    printf("Common chars in \"%s\" and \"%s\" are: ", x, y); 
    commonChars(x,y); 
    putchar('\n');
    ror(x);
    printf("Right-rotated: \"%s\"\n", x);
    rol(x);
    printf("Left-rotated: \"%s\"\n", x);
    sP = strCopy(z, x);
    printf("sP: \"%s\", z: \"%s\"\n", sP, z);
    
    if((sP = substring(x, y)) == NULL) 
        printf("\"%s\" is not a substring of \"%s\"\n", y, x) ;
    else {
        printf("\"%s\" is a substring of \"%s\"", y, x) ;
        printf(" from index %d\n", (int)(sP-x)) ;
    }    

    return 0;
}