c语言将2进制数转化为10进制数（栈的初始化，进栈，出栈）

//c语言描述  将2进制转化为10进制
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define STACK_INIT_SIZE 20
#define     //栈满后再分配

typedef char ElemType;
typedef struct
{
    ElemType *base;   //栈底
    ElemType *top;     //栈底
    int stackSize;      // 栈的容量
}sqStack;

void InitStack (sqStack *s)    //初始化栈
{
       s -> base = (ElemType*) malloc(STACK_INIT_SIZE);
       if(! s-> base)
       { 
           printf("分配空间失败");
           exit(0);
       }
      s->top=s->base ;
      s->stackSize = STACK_INIT_SIZE;
}

void Push (sqStack *s, ElemType e)   //进栈
{
       if(s->top - s->base >= s->stackSize)
       {
             s->base =(ElemType*) realloc(s->base,(s->stackSize + STACKINCREMENT) * sizeof(ElemType));//分配空间
                    if(! s-> base)
                   { 
                     printf("分配空间失败");
                     exit(0);
                   }
       }
       *(s->top) = e;           //先赋值
       s->top++;               //指针在+1
}

void Pop(sqStack * s,ElemType *e)    //出栈
{
    if(s->top == s->base )
    {
       printf("栈为空，没法出栈");
           return;
    }
    *e = *--(s->top);    //首先把s->top的元素赋值给e 再将地址--
}

     
int StackLen (sqStack s)    //返回栈有多少个元素
{
   return ( s.top - s.base);  //  实质是地址相减 除以ElemType 
} 


int main()
{
    ElemType c;  //声明一个字符c
    sqStack s;   //声明一个结构体s

    int len,i,sum=0;  
    InitStack(&s);     //初始化栈
    printf("请输入二进制数，输入#结束！
");
    scanf("%c",&c);
    while( c != '#')
    {
       Push (&s,c);
       scanf ("%c",&c);
    }
     getchar();   //接收回车键
     len =StackLen(s);
     printf("栈的当容量：%d
",len);
     for(i=0; i<len ; i++)
     {
        Pop(&s,&c);
         sum = sum + (c-48) * pow(2,i);
     }
     printf("转化为十进制数为:%d 
",sum);

     return 0;
}