随机大数产生

听AC大神说随机大数不能用两个随机数乘，所以就用每一位来rand

 

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#define MAX 10000000
int Rand(int k,int max)
{
   int     a = 0;
    for(int i =1;i <= k;i ++)
    {
       a *= 10;
       a += rand()%10;
    }
    if(a <= max)
     return a;
    else return Rand(k,max);

}

int main(){
    freopen("input.txt","w",stdout);
    srand( (int)time( NULL ));
    printf("%d
",MAX);
    for(int i =1 ;i<= MAX;i ++)
     {
       printf("%d
",Rand(4,9999));
     }
     //printf("%d
",Rand(9));
  return 0;
}