Eroare de compilare: user.c: In function ‘main’: user.c:9:40: error: expected ‘)’ before ‘;’ token s+=((x[i]*y[i+1]-x[i+1]*y[i])/2; ^ user.c:11:1: error: expected ‘;’ before ‘}’ token } ^ user.c:5:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("aria.in","r",stdin),freopen("aria.out","w",stdout),scanf("%d",&n); ^ user.c:5:41: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("aria.in","r",stdin),freopen("aria.out","w",stdout),scanf("%d",&n); ^ user.c:5:70: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("aria.in","r",stdin),freopen("aria.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("%Lf%Lf",x+i,y+i); ^