Compilare: main.c: In function 'main': main.c:13:23: warning: suggest parentheses around '-' inside '<<' [-Wparentheses] a[c&~(1<<i-2)]=0; ~^~ main.c:9:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("coins.in","r",stdin),freopen("coins.out","w",stdout),scanf("%d",&m),memset(a,-1,sizeof(a)); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:9:35: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("coins.in","r",stdin),freopen("coins.out","w",stdout),scanf("%d",&m),memset(a,-1,sizeof(a)); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:9:67: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("coins.in","r",stdin),freopen("coins.out","w",stdout),scanf("%d",&m),memset(a,-1,sizeof(a)); ^~~~~~~~~~~~~~ main.c:32:13: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&b); ^~~~~~~~~~~~~~