Compilare: main.cpp: In function 'int main()': main.cpp:3:78: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int a[Nmax][Nmax];int n,k;int main(){int t,i,j,l;freopen("perm.in","r",stdin);freopen("perm.out","w",stdout);scanf("%d %d", &n,&k);a[1][0]=1;for (i=2;i<=n;++i)for (j=i;j>=1;--j)for (t=0,l=0;l<=400;++l){t=(a[j][l]=a[j][l]*(i-1)+a[j-1][l]+t)/10;a[j][l]%=10;}for (i=400;(--i) && a[k][i]==0;);while(i>=0){printf("%d",a[k][i]);i--;}return 0;} ^ main.cpp:3:109: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int a[Nmax][Nmax];int n,k;int main(){int t,i,j,l;freopen("perm.in","r",stdin);freopen("perm.out","w",stdout);scanf("%d %d", &n,&k);a[1][0]=1;for (i=2;i<=n;++i)for (j=i;j>=1;--j)for (t=0,l=0;l<=400;++l){t=(a[j][l]=a[j][l]*(i-1)+a[j-1][l]+t)/10;a[j][l]%=10;}for (i=400;(--i) && a[k][i]==0;);while(i>=0){printf("%d",a[k][i]);i--;}return 0;} ^ main.cpp:3:131: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] int a[Nmax][Nmax];int n,k;int main(){int t,i,j,l;freopen("perm.in","r",stdin);freopen("perm.out","w",stdout);scanf("%d %d", &n,&k);a[1][0]=1;for (i=2;i<=n;++i)for (j=i;j>=1;--j)for (t=0,l=0;l<=400;++l){t=(a[j][l]=a[j][l]*(i-1)+a[j-1][l]+t)/10;a[j][l]%=10;}for (i=400;(--i) && a[k][i]==0;);while(i>=0){printf("%d",a[k][i]);i--;}return 0;} ^