Compilare: user.c: In function ‘main’: user.c:4:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("cc.in","r",stdin),freopen("cc.out","w",stdout),scanf("%d",&n); ^ user.c:4:39: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("cc.in","r",stdin),freopen("cc.out","w",stdout),scanf("%d",&n); ^ user.c:4:66: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("cc.in","r",stdin),freopen("cc.out","w",stdout),scanf("%d",&n); ^ user.c:7:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&k),v[i][n+j+1]=k,v[n+j+1][i]=-k,c[i][n+j+1]=1; ^