#include #include int main(void) { FILE *fp; char line[255]; int valid = 0; fp = fopen("input", "r"); if(fp == NULL) { perror("Error opening file."); return(-1); } while(fgets(line, sizeof(line), fp) != NULL) { int start, end; char subject; char password[64]; sscanf(line, "%d-%d %c: %s\n", &start, &end, &subject, password); if(password[start - 1] == subject && password[end - 1] != subject || password[end - 1] == subject && password[start - 1] != subject) valid++; } fclose(fp); printf("There are %d valid passwords\n", valid); }