跪求。。数据结构 任意整数的四则运算

很麻烦啊 别忘了给分 #include #include #include char str1[1024] = {0}; char sign = 0; struct node { int num; struct node* next; }; struct node* head1; struct node* head2; struct node* head3; void InitList() { head1 = (struct node*)malloc(sizeof(struct node