Compilare: user.cpp: In function ‘int ok(int)’: user.cpp:69:12: warning: unused variable ‘r’ [-Wunused-variable] int j, r = 0, isok = 0; ^ user.cpp: In function ‘void init()’: user.cpp:88:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp: In function ‘void read()’: user.cpp:25:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("div.in", "r", stdin); ^ user.cpp:26:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &k); ^ user.cpp:27:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s + 1); ^ user.cpp: In function ‘void write()’: user.cpp:124:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("div.out", "w", stdout); ^ /tmp/ccCugwxY.o: In function `read()': user.cpp:(.text+0xc4): warning: the `gets' function is dangerous and should not be used.