Compilare: user.cpp: In function ‘int main()’: user.cpp:37:18: warning: unused variable ‘ok’ [-Wunused-variable] bool ok = false; ^ user.cpp:52:18: warning: unused variable ‘ok’ [-Wunused-variable] bool ok = false; ^ user.cpp:7:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.in","r",stdin); ^ user.cpp:8:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qmatrix.out","w",stdout); ^ user.cpp:9:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d\n", &N, &x,&y, &op); ^ user.cpp:31:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c%d%d\n", &Op, &ord, &nr); ^