后缀表达式求值 用链表做的 输入什么都一直输出1

Question

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

typedef struct Node{
int data;
struct Node* pNext;
}NODE,*PNODE;

typedef struct Stack{
PNODE pTop;
PNODE pBottom;
}STACK,*PSTACK;

void Ini(PSTACK);
void Push(PSTACK,char);
bool Pop(PSTACK,char*);
bool is_empty(PSTACK);
int Qiuzhi(PSTACK,char*);
int main(int argc, const char * argv[]) {
STACK S;
Ini(&S);
char str[100];
gets(str);
printf("%d",Qiuzhi(&S,str)) ;

return 0;

}
int Qiuzhi(PSTACK pS,char* str){
int i,oc,count=0;
char R;
char L;
char OC;
for(i=0;i<strlen(str);i++){

           if(str[i]>='0'&&str[i]<='9'){
               Push(pS, str[i]);
               count++;
           }
           if(count==2){
               Pop(pS, &R);
               Pop(pS, &L);
               switch (str[2]){
                   case '+':
                    
                       oc= ((L)-'0')+((R)-'0');
                       break;
                   case '-':
                      
                       oc= ((L)-'0')-((R)-'0');
                       break;
                   case '*':
                       
                       oc= ((L)-'0')*((R)-'0');
                       break;
                   case '/':
                       
                       oc= ((L)-'0')/((R)-'0');
                       break;
               }
               OC=oc+48;
               Push(pS, OC);
               count=1;
           }
       }
return oc;

}

void Ini(PSTACK pS){
pS->pTop=(PNODE)malloc(sizeof(NODE));
pS->pBottom=pS->pTop;
pS->pTop->pNext=NULL;

}

void Push(PSTACK pS,char a){
PNODE pNew=(PNODE)malloc(sizeof(NODE));
pNew->data=a;
pNew->pNext=pS->pTop;
pS->pTop=pNew;
}

bool is_empty(PSTACK pS){
if(pS->pTop==pS->pBottom) return true;
else return false;
}

bool Pop(PSTACK pS,char* pVal){
if(is_empty){
return false;
}
else{
PNODE r=pS->pTop;
*pVal=r->data;
pS->pTop=r->pNext;
free(r);
r=NULL;
}
}

Answer 1

char * a;
char * b;
指针没分配空间啊。定义成 char a,b;就行了
Pop(&S, a);
Pop(&S, b);
改为
Pop(&S, &a);
Pop(&S, &b);
后面的 * a, * b都改为a和b