数字拆解

//特殊乘法

#include <stdio.h>
int main()
{
int a,b;
while(scanf("%d%d",&a,&b) != EOF)
{
int buf1[20],buf2[20],size1 = 0,size2 = 0;
do
{
buf1[size1++] = a % 10;
a  /= 10;
}while(a != 0);
do
{
buf2[size2++] =b % 10;
b /= 10;
}while(b != 0);
int ans = 0;
for (int i = 0; i < size1; ++i)
{
for (int j = 0; j < size2; ++j)
{
ans += buf1[i] * buf2[j];
}
}
printf("%d\n",ans);
}
return 0;
}

//数字拆解加强版，使用字符串解决，避免了数学方法
#include <stdio.h>
int main()
{
char a[11],b[11];
while(scanf("%s%s",a,b) != EOF)
{
int ans = 0;
for (int i = 0; a[i] != 0; ++i)
{
for (int j = 0; b[j] != 0; ++j)
{
ans += (a[i] - '0') * (b[j] - '0');
}
}
printf("%d\n",ans );
}
return 0;
}