Binary and decimal conversion

Binary Decimal procedure is as follows:

Thinking: determining whether each binary "1", if "1", plus bits corresponding to the multiple of 2.

#include<stdio.h>
int main()
{
	long num,a=10,b=1,add=0;
	printf("输入的二进制数为：");
	scanf("%d",&num);
	while(num!=0)
	{
		add=add+(num%a ? b : 0);
		num=num-num%a;
		a=a*10;
		b=b*2;
	}
	printf("输出的十进制数为：%d\n",add);
}

Decimal Binary transfer procedure is as follows:

#include<stdio.h>
int main()
{
	long num,binNum=0,a=1;
	printf("输入的十进制数为：");
	scanf("%d",&num);
	while(num!=0)
	{
		binNum+=(num%2)*a;
		num=num/2;
		a*=10;
	}
	printf("输出的二进制数为：%d\n",binNum);
}