Compilare: user.c: In function ‘push’: user.c:23:21: warning: implicit declaration of function ‘malloc’ [-Wimplicit-function-declaration] p = (struct node*) malloc(sizeof(struct node)); ^ user.c:23:28: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] p = (struct node*) malloc(sizeof(struct node)); ^ user.c: At top level: user.c:46:6: warning: return type of ‘main’ is not ‘int’ [-Wmain] void main() { ^ user.c: In function ‘main’: user.c:47:10: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in","r",stdin); ^ user.c:48:10: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out","w",stdout); ^ user.c:52:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.c:53:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m); ^ user.c:62:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &i, &j); ^