my高精模板

网上的鱼龙混杂，不如自己写个。

char str[1000];
int a[1000],b[1000],c[1000];

int main(){
    scanf("%s",str);
    int len = strlen(str);
    for(int i = len-1;i >= 0;i--)a[len-i] = str[i]-'0';
    scanf("%s",str);
    int n = len;
    len = strlen(str);
    for(int i = len-1;i >= 0;i--)b[len-i] = str[i]-'0';
    int m = len;
    n = max(n,m); 
    
    for(int i = 1;i <= n;i++)c[i] = a[i]+b[i];
    for(int i = 1;i <= n;i++)c[i+1] += c[i]/10,c[i] %= 10;
    while(c[n] > 10||c[n+1])c[n+1] += c[n]/10,c[n] %= 10,n++;
    
    for(int i = n;i > 0;i--)putchar(c[i]+'0');putchar('
');
    
return 0;
}

char s[1000];
int b;
int a[1000],c[1000];
int n,m;

int main(){
    scanf("%s",s);
    int n = strlen(s);
    for(int i = n-1;i >= 0;i--)a[n-i] = s[i] - '0';
    scanf("%d",&b);
    
    for(int i = 1;i <= n;i++)c[i] = a[i]*b;
    for(int i = 1;i <= n;i++)c[i+1] += c[i]/10,c[i] %= 10;
    while(c[n] > 10||c[n+1])c[n+1] += c[n]/10,c[n] %= 10,n++;
    
    for(int i = n;i >= 1;i--)putchar(c[i]+'0');
    
return 0;
}

#include<iostream>
#include<cstdio> 
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<algorithm>
using namespace std;

struct bignum{
    int a[1000];
    int len;
    
    void init(){memset(a,0,sizeof(a));}
    
    void get(){
        init();
        char s[1000];
        scanf("%s",s);
        len = strlen(s);
        for(int i = len-1;i >= 0;i--)a[len-i] = s[i]-'0';
    }
    
    void print(){
        for(int i = len;i > 0;i--)putchar(a[i]+'0');
    }
    
    void initlen(){
        for(len = 999;len > 0;len--)if(a[len])break;
    }
    
    bignum operator *(const bignum& x){
        bignum ans;
        ans.init();
        for(int i = 1;i <= len;i++)
            for(int j = 1;j <= x.len;j++)
                ans.a[i+j-1] += a[i]*x.a[j];
        for(int i = 1;i < 1000;i++)ans.a[i+1] += ans.a[i]/10,ans.a[i] %= 10;
        ans.initlen();
        return ans;
    }
    
}x,y,z;

bignum div(bignum x,int y){
    bignum ans;
    ans.init();
    int now = 0,cur = x.len+1;
    while(now < y){
        cur--;
        now = now*10+x.a[cur];
    }
    ans.len = cur;
    while(cur){
        ans.a[cur] = now/y; cur--;
        now = now%y*10+x.a[cur];
    }
    return ans;
}

int w;

int main(){
    x.get(); cin >> w;
    div(x,w).print();
return 0;
}