Compilare: main.cpp: In function 'int main()': main.cpp:7:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("zone.in","r",stdin); ^ main.cpp:8:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("zone.out","w",stdout); ^ main.cpp:10:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:12:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^ main.cpp:15:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^ main.cpp:58:58: warning: 'p2' may be used uninitialized in this function [-Wmaybe-uninitialized] v2[2]=a[n][j]-a[p2][j]; ~~~~~~~^