Compilare: main.c: In function 'D': main.c:31:12: warning: implicit declaration of function 'abs' [-Wimplicit-function-declaration] if(abs(d[i].y-a[m].x)<=r) ^~~ main.c: In function 'main': main.c:43:5: warning: implicit declaration of function 'qsort' [-Wimplicit-function-declaration] qsort((void*)(a+1),n,sizeof(a[1]),A); ^~~~~ main.c:40:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.in","r",stdin),freopen("cmap.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:40:34: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.in","r",stdin),freopen("cmap.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:40:65: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.in","r",stdin),freopen("cmap.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~ main.c:42:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&a[i].x,&a[i].y); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~