Wuhan University of Science and Technology acm:1009: Chinese Edition C language Programming tutorial (second Edition) example 4.18

Problem Description

Verify Goldbach conjecture that any even number of sufficiently large (>=4) can be represented by a sum of two primes.

Input

Enter an even n. (2<n<=10000)

Output

Find A, B make n=a+b

Where A and B are two primes, and a<=b.

Sample Input

4

100

Sample Output

2 2

3 97

1#include <iostream>2 3#include <math.h>4 5 using namespacestd;6 7 intPrimeintm)8 9 {Ten  One          intI,n; A  -          if(m==1)return 0; -  theN= (int) sqrt (Double) m); -  -           for(i=2; i<=n;i++) -  +                    if(m%i==0)return 0; -  +                    return 1; A  at } -  - intMain () -  - { -  in          intCount,i,number; -  toCount=0; +  -           while(cin>>Number ) the  *          { $ Panax Notoginseng                     for(i=2; i<=number/2; i=i+1) -  the                             if(Prime (i) &&prime (number-i)) +  A                             { the  +cout<<i<<" "<<number-i<<Endl; -  $                                       Break; $  -                             } -  the          } - Wuyi          return 1; the  -}

Other code:

1#include <stdio.h>2#include <math.h>3 intPrime (intm)4 {5     intr = m/2;6      for(inti =2; I <= R; i++)7         if(m% i = =0)8             return 0;9     return 1;Ten } One intMain () A { -     intn,i; -      while(~SCANF ("%d",&N)) the     { -          for(i=2; i<=n/2; i++) -             if(Prime (i) &&prime (ni)) { -printf"%d%d\n", i,n-i); +                  Break; -             } +     } A     return 0; at}

Wuhan University of Science and Technology acm:1009: Chinese Edition C language Programming tutorial (second Edition) example 4.18