二进制数转换成十进制数（栈来实现）

补充知识点：
头文件：#include <math.h>
pow() 函数用来求 x 的 y 次幂（次方），其原型为： double pow(double x, double y);

栈：先进后出   队列：先进先出

main.c
#include "stdio.h"
#include "math.h"
#define STACK_INIT_SIZE 20
#define STACKINCREMENT 10

typedef char ElemType;
typedef struct{
ElemType *base;
ElemType *top;
int stacksize;
}sqStack;

initStack(sqStack *s)
{
/*内存中开辟一段连续空间作为栈空间，首地址赋值给s->base*/
s->base = (ElemType *)malloc(STACK_INIT_SIZE * sizeof(ElemType));
if(!s->base) exit(0); /*分配空间失败*/
s->top = s->base; /*最开始，栈顶就是栈底*/
s->stacksize = STACK_INIT_SIZE; /*最大容量为STACK_INIT_SIZE */
}
Push(sqStack *s, ElemType e){
if(s->top - s->base >= s->stacksize){
/*栈满，追加空间*/
s->base = (ElemType *)realloc(s->base, (s->stacksize +
STACKINCREMENT)*sizeof(ElemType));
if(!s->base) exit(0); /*存储分配失败*/
s->top = s->base + s->stacksize;
s->stacksize = s->stacksize + STACKINCREMENT; /*设置栈的最大容量*/
}
*(s->top) = e; /*放入数据*/
s->top++;
}

Pop(sqStack *s , ElemType *e){
if(s->top == s->base) return;
*e = *--(s->top);
}

int StackLen(sqStack s){
return (s.top - s.base) ;
}
main()
{
ElemType c;
sqStack s;
int len , i , sum = 0;
printf("Please input a Binary digit\n");

initStack(&s); /*创建一个栈，用来存放二进制字符串*/
/*输入0/1字符表示的二进制数，以#结束*/
scanf("%c",&c);
while(c!='#')
{
Push(&s,c);
scanf("%c",&c);
}
getchar();
len = StackLen(s); /*得到栈中的元素个数，即二进制数的长度*/

for(i=0;i<len;i++){
Pop(&s,&c);
sum = sum + (c-48) * pow(2,i); /*转换为十进制*/
}
printf("Decimal is %d\n",sum);
getche();
}