救救80蒟蒻吧

#include<iostream>
#include<cstring>
#include<string>
#include<cstdio>
#define maxn 1001
using namespace std;
struct bigint{
    int len,a[maxn];
    bigint(){
        len=0;
        memset(a,0,sizeof(a));
    }
    int &operator[](int i){
        return this->a[i];
    } 
    void operator=(string s){
        this->len=s.length();
        int tmp=len;
        while(this->a[++tmp]){
            this->a[tmp]=0;
        }
        for(int i=1;i<=len;i++){
            this->a[i]=s[len-i]-'0';
        }
    } 
    void operator=(bigint b){
        this->len=b.len;
        int tmp=len;
        while(this->a[++tmp]){
            this->a[tmp]=0;
        }
        for(int i=1;i<=len;i++){
            this->a[i]=b.a[i];
        }
    }
    void carry(int ln){
        len=ln;
        for(int i=1;i<=this->len;++i){
            this->a[i+1]+=this->a[i]/10;
            this->a[i]%=10;
        }
        while(!this->a[this->len])
            --len;
    }
    void out(){
        for(int i=max(this->len,1);i;i--){
            printf("%d",this->a[i]);
        }
    }
};
bigint operator*(bigint a,bigint b){
    bigint c;
    memset(c.a,0,sizeof(c.a));
    int lena=a.len;
    int lenb=b.len;
    for(int i=1;i<=lena;i++){
        for(int j=1;j<=lenb;j++){
            c.a[i+j-1]+=a.a[i]*b.a[j];
        }
    }
    c.carry(lena+lenb+1);
    return c;
}
int main(){
    bigint a,b,c;
    string A,B;
    cin>>A>>B;
    a=A;
    b=B;
    c=a*b;
    c.out();
    return 0;
}