Compilare: user.c: In function ‘main’: user.c:10:9: warning: implicit declaration of function ‘abs’ [-Wimplicit-function-declaration] scanf("%d",&x),p[i+j]+=x,p[2*n-1+abs(i-j)+(i>j?(n-1):0)]+=x; ^ user.c:7:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("diagonale.in","r",stdin),freopen("diagonale.out","w",stdout),scanf("%hd",&n); ^ user.c:7:46: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("diagonale.in","r",stdin),freopen("diagonale.out","w",stdout),scanf("%hd",&n); ^ user.c:7:80: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("diagonale.in","r",stdin),freopen("diagonale.out","w",stdout),scanf("%hd",&n); ^ user.c:10:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x),p[i+j]+=x,p[2*n-1+abs(i-j)+(i>j?(n-1):0)]+=x; ^