Compilare: user.cpp: In function ‘void prep()’: user.cpp:22:13: warning: unused variable ‘k’ [-Wunused-variable] int i,j,k,OK,i1; ^ user.cpp:22:15: warning: unused variable ‘OK’ [-Wunused-variable] int i,j,k,OK,i1; ^ user.cpp:22:18: warning: unused variable ‘i1’ [-Wunused-variable] int i,j,k,OK,i1; ^ user.cpp: In function ‘int main()’: user.cpp:35:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("luna.in", "r", stdin); ^ user.cpp:36:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("luna.out", "w", stdout); ^ user.cpp:37:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:40:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m[i][j]); ^ user.cpp:63:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^ user.cpp:65:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&color,&l1,&l2); ^