Compilare: user.cpp: In function ‘int main()’: user.cpp:58:19: warning: unused variable ‘sum1’ [-Wunused-variable] int lin1=0,lin2=0,sum1=0,sum2=0; ^~~~ user.cpp:58:26: warning: unused variable ‘sum2’ [-Wunused-variable] int lin1=0,lin2=0,sum1=0,sum2=0; ^~~~ user.cpp:5:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("magic2.in","r",stdin); ^ user.cpp:6:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("magic2.out","w",stdout); ^ user.cpp:8:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:11:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i][j]); ^