Compilare: user.cpp: In function ‘int main()’: user.cpp:47:9: warning: unused variable ‘xc’ [-Wunused-variable] int xc, yc, hc; ^ user.cpp:47:13: warning: unused variable ‘yc’ [-Wunused-variable] int xc, yc, hc; ^ user.cpp:47:17: warning: unused variable ‘hc’ [-Wunused-variable] int xc, yc, hc; ^ user.cpp:33:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("volum.in", "r", stdin); ^ user.cpp:34:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("volum.out", "w", stdout); ^ user.cpp:35:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:38:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^