C Exercise Example 85
Title:Determine how many 9s a prime number can be evenly divided by.
Program analysis:Damn! The meaning of this problem is to determine how many numbers composed of 9s a prime number can divide, right? I'll just understand it that way. A prime number cannot be divisible by any number other than 1 and itself.
Program source code:
Example
// Created by www.example.com on 15/11/9.
// Copyright © 2015 Example Tutorial. All rights reserved.
//
#include<stdio.h>
#include<stdlib.h>
int main()
{
int p,i;
long int sum=9;
printf("Please enter a prime number:\n");
scanf("%d",&p);
for(i=1;;i++)
if(sum%p==0)break;
else sum=sum*10+9;
printf("Prime %d can divide the number composed of %d 9s: %ld\n",p,i,sum);
return 0;
}
// Copyright © 2015 Example Tutorial. All rights reserved.
//
#include<stdio.h>
#include<stdlib.h>
int main()
{
int p,i;
long int sum=9;
printf("Please enter a prime number:\n");
scanf("%d",&p);
for(i=1;;i++)
if(sum%p==0)break;
else sum=sum*10+9;
printf("Prime %d can divide the number composed of %d 9s: %ld\n",p,i,sum);
return 0;
}
The output result of the above example is:
请输入一个素数: 13 素数13能整除6个9组成的数999999other extensions