#include <iostream>
using namespace std;

//链栈
#define ElemType char

typedef struct LNODE{
    ElemType elem;
    struct LNODE *next;
}SqStack;

SqStack * InitStack(SqStack *S){
      char ch;
      
      SqStack *p;
      S=NULL;
      ch=getchar( );
      while (ch!='\n'){
           p=(SqStack*)malloc(sizeof(SqStack));
           p->elem=ch;
           p->next=S;
           S=p;
              ch=getchar( );
      }
      return S;
}
/*void InitStack(SqStack *S){
      char ch;
      
      SqStack *p;
      S=NULL;
      ch=getchar( );
      while (ch!='\n'){
           p=(SqStack*)malloc(sizeof(SqStack));
           p->elem=ch;
           p->next=S;
           S=p;
              ch=getchar( );
      }
}*/


void DestoryStack(SqStack *Sq){
    SqStack *S;
    while(S){
        S=Sq;
        Sq=Sq->next;
        free(S);
    }
}

bool GetTop(SqStack *Sq,ElemType &e){
    SqStack *S;
    S=Sq;
    if(!S)return false;
    e=S->elem;
    return true;
}

SqStack * Push_sq(SqStack *Sq,ElemType e){
    SqStack *SNEW;
    SNEW=(SqStack *)malloc(sizeof(SqStack));
    SNEW->elem=e;
    SNEW->next=Sq;
    Sq=SNEW;
    return Sq;
}

bool Pop_sq(SqStack *Sq,ElemType &e){
   
    SqStack *S;
    S=Sq;
    if(!S)return false;
    e=S->elem;
    Sq=Sq->next;
    free(S);
    return true;
}

void PrintStack(SqStack *Sq){
    SqStack *S;
    S=Sq;
    while(S){
        cout<<S->elem<<' ';
        S=S->next;
    }
    cout<<endl;
}

int main(void){
    SqStack *S;
    ElemType e;
        S=InitStack(S);
    PrintStack(S);
//    S=Push_sq(S,'d');
    Pop_sq(S,e);
    PrintStack(S);
    return 0;
}
POP和PUSH函数作用之后，新的堆栈无法提供给print函数使用，调试发现结构体没有传出来，这是怎么回事，哪里需要修改

void Push_sq(SqStack *Sq,ElemType e){
    SqStack *SNEW;
    SNEW=(SqStack *)malloc(sizeof(SqStack));
    SNEW->elem=e;
    SNEW->next=Sq;
    Sq=SNEW;

}
原程序是这么定义PUSH的