Compilare: main.cpp: In function 'int main()': main.cpp:11:23: warning: unused variable 'k' [-Wunused-variable] int n,i,j,k,cnt=0; ^ main.cpp:11:25: warning: unused variable 'cnt' [-Wunused-variable] int n,i,j,k,cnt=0; ^~~ main.cpp:9:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("custi.in","r",stdin); ^ main.cpp:10:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("custi.out","w",stdout); ^ main.cpp:12:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:15:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^