Compilare: user.cpp: In function ‘void smart()’: user.cpp:14:13: warning: unused variable ‘j’ [-Wunused-variable] int i, j, k; ^ user.cpp:14:16: warning: unused variable ‘k’ [-Wunused-variable] int i, j, k; ^ user.cpp: In function ‘int main()’: user.cpp:52:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,k; ^ user.cpp:49:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.in", "r", stdin); ^ user.cpp:50:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv5.out", "w", stdout); ^ user.cpp:51:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d\n", &n, &p, &u); ^ user.cpp:55:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(lin); ^ /tmp/ccvPg9UO.o: In function `main': user.cpp:(.text.startup+0x98): warning: the `gets' function is dangerous and should not be used.