大数相乘

#include <bits/stdc++.h>
using namespace std;

void reverse(char *str)
{
	int length=strlen(str);
	for (int i=0;i<length/2;i++)
	{
		int t=str[i];
		str[i]=str[length-1-i];
		str[length-1-i]=t;
	}
}

int main()
{
	int T;
	scanf("%d",&T);
	while (T--)
	{
		char s1[200]={0},s2[200]={0},ans[200][200]={{0}},result[200]={0};
		scanf("%s%s",s1,s2);
		int length1=strlen(s1);
		int length2=strlen(s2);
		reverse(s1);
		reverse(s2);
		s1[length1]=s2[length2]=0;
		int i,j,carry=0;
		for (i=0;i<length2;i++)
		{
			carry=0;
			for (j=i;j<i+length1;j++)
			{
				int s1pos=j-i;
				ans[i][j]=((s2[i]-'0')*(s1[s1pos]-'0')+carry)%10+'0';
				carry=((s2[i]-'0')*(s1[s1pos]-'0')+carry)/10;
			}
			if (carry!=0) ans[i][j]=carry+'0';
		}
		int maxlength;
		if (ans[length2-1][length2+length1-1]==0)
			maxlength=length1+length2-2;
		else
			maxlength=length1+length2-1;
		carry=0;
		int total;
		for (i=0;i<=maxlength;i++)
		{
			total=carry;
			for (j=0;j<length2;j++)
			{
				if (ans[j][i]==0)
					ans[j][i]='0';
				total+=ans[j][i]-'0';
			}
			carry=total/10;
			result[i]=total%10+'0';
		}
		if (carry!=0) result[i++]=carry+'0';
		result[i]=0;
		for (i=strlen(result)-1;i>=1;i--)
			if (result[i]=='0')
				result[i]=0;
			else
				break;
		reverse(result);
		printf("%sn",result);
	}
}