Compilare: user.cpp: In function ‘int main()’: user.cpp:111:17: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[++ n] = NULL; ^ user.cpp:79:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, m, x, y; ^ user.cpp:77:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("kinetic.in", "r", stdin); ^ user.cpp:78:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("kinetic.out", "w", stdout); ^ user.cpp:81:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:83:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n", &a[i], &b[i]); ^ user.cpp:87:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/cc5fYqvS.o: In function `main': user.cpp:(.text.startup+0xce): warning: the `gets' function is dangerous and should not be used.