Comment on the output of this C code?    int main()    {        char c;        int i = 0;        FILE *file;        file = fopen("test.txt", "w+");        fprintf(file, "%c", 'a');        fprintf(file, "%c", -1);        fprintf(file, "%c", 'b');        fclose(file);        file = fopen("test.txt", "r");        while ((c = fgetc(file)) !=  -1)            printf("%c", c);        return 0;.    }