Compilare: main.c: In function 'main': main.c:35:11: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses] if(!c[i]) ^ main.c:27:2: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r",stdin),freopen("biconex.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:27:34: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r",stdin),freopen("biconex.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:27:68: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r",stdin),freopen("biconex.out","w",stdout),scanf("%d%d",&n,&m); ^~~~~~~~~~~~~~~~~~~ main.c:29:6: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",a+i,b+i),++w[a[i]],++w[b[i]]; ^~~~~~~~~~~~~~~~~~~~~