Compilare: user.c: In function ‘quicksort’: user.c:6:23: warning: unused variable ‘t’ [-Wunused-variable] int pivot,j,i,aux,t; ^ user.c: In function ‘main’: user.c:42:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("excel.in","r",stdin); ^ user.c:43:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("excel.out","w",stdout); ^ user.c:67:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&a[3][n]); ^