ISBN::ISBN(const char* str, const ISBNPrefix& list){ // Constructor With Arguements To Set The ISBN -
                                                     // Back To It's Previous State.
        char s[11];

        strcpy(isbn, str);
        int val;
        int a = 0;
        int b = 0;
        int c;

        reg = decode(list);
        val = valid(str);

        if(val == 1 && reg == 1){

                        mod[0] = '-';
                        mod[1] = '\0';
        }
        else if(reg == 0){

                for(c = 0; c < 5 && (isbn[c] != '\0'); c++){  // For Loop To Add Area Back To ISBN.
                         area[c] = isbn[c];
                         area[c + 1] = '\0';
                }
                for(c = (strlen(area) - 1); c < 7; c++){   // For Loop To Add Publisher Back To ISBN.
                        publisher[b] = isbn[c];
                        publisher[b + 1] = '\0';
                        b++;
                }
                for(int c = ((strlen(area)) + (strlen(publisher))); c < 9; c++){ // For Loop To Add Title Back To ISBN.
                        title[a] = isbn[c];
                        title[a+1] = '\0';
                        a++;

                               mod[0] = '\0';
                        }
        }
        else{

               *this = ISBN();  // Returns Current Object.
        }

}