代码贴上：

#include<iostream>
#include<stdio.h>
#include<cstring>
using namespace std;

const int maxsize = 2010;

char s[maxsize] = {0};
int a[maxsize] = {0};
int lena;
int b[maxsize] = {0};
int lenb;
int c[maxsize] = {0};
int lenc;

int main(){
	scanf("%s",s);
	lena = strlen(s);
	for(int i=0;i<lena;i++){
		a[i] = s[lena - i - 1] - '0';
	}
	scanf("%s",s);
	lenb = strlen(s);
	for(int i=0;i<lenb;i++){
		b[i] = s[lenb - i - 1] - '0';
	}
	for(int i=0;i<maxsize;i++){
		for(int j=0;j<maxsize;j++){
			c[i+j] += a[j] * b[i];
		}
	}
	for(int i=0;i<maxsize;i++){
		if(c[i]!=0){
			c[i+1]+=c[i] / 10;
			c[i] = c[i] % 10;
		}
	}
	
	for(int i=maxsize - 1;i>=0;i--){
		if(c[i]!=0){lenc=i+1;break;}
	}
	
	for(int i=lenc - 1;i>=0;i--){
		cout<<c[i];
	}
	
	return 0;
}