1
Stack CreateStack( int MaxSize ){
2
    Stack s = (Stack) malloc(sizeof(struct SNode));
3
    s->Top1 = -1;
4
    s->Top2 = MaxSize;
5
    s->MaxSize = MaxSize;
6
    s->Data = (ElementType*) malloc(sizeof(ElementType)*MaxSize);
7
    return s;
8
}

1
bool Push( Stack S, ElementType X, int Tag ) {
2
    if( S->Top1 + 1 == S->Top2 ) {
3
        printf("Stack Full\\\\n");
4
        return false;
5
    }
6
    if( Tag == 1 ) {
7
        S->Data[++S->Top1] = X;
8
    } else {
9
        S->Data[--S->Top2] = X;
10
    }
11
    return true;
12
}