Compilare: user.cpp: In function ‘int main()’: user.cpp:15:22: warning: unused variable ‘val’ [-Wunused-variable] int n,i,j,lgmax,temp,val,k,x,y,x1,y1,inf,sup,l,c; ^ user.cpp:12:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pietre2.in","r",stdin); ^ user.cpp:13:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pietre2.out","w",stdout); ^ user.cpp:18:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:20:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(j=1;j<=n;++j) scanf("%d",&mat[i][j]); ^