Compilare: user.cpp: In function ‘void read()’: user.cpp:50:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &p); ^ user.cpp:52:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1; i<=n; ++i) scanf("%d", &A[i]), mp[A[i]] = 0; ^ user.cpp:53:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1; i<=m; ++i) scanf("%d", &B[i]), mp[B[i]] = 0; ^ user.cpp:54:57: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1; i<=p; ++i) scanf("%d", &C[i]), mp[C[i]] = 0; ^ user.cpp: In function ‘int main()’: user.cpp:67:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pedefe.in", "r", stdin); ^ user.cpp:68:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pedefe.out", "w", stdout); ^