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  1. #include <stdio.h>
  2.  
  3. //関数のプロトタイプ宣言
  4. void goldbach(int n);
  5. void print(int a, int b);
  6. int prime(int n);
  7.  
  8. //main関数
  9. int main(void){
  10.     int a;
  11.  
  12.     scanf("%d", &a);
  13.     goldbach(a);    
  14.  
  15.     return 0;
  16. }
  17.  
  18. // ゴールドバッハ予想
  19. void goldbach(int n){
  20.     int i;
  21.     for(i=2; i<=n/2; i++){
  22.         if(prime(i) && prime(n-i)){
  23.             print(i, n-i);
  24.         }
  25.     }
  26. }
  27.  
  28. //結果表示
  29. void print(int a, int b){
  30.     static int count = 0;
  31.     count++;
  32.     printf("%2d: %d = %d + %d\n", count, a+b, a, b);
  33. }
  34.  
  35. //素数判定
  36. int prime(int n){
  37.     int i;
  38.     int sosuu = 1;
  39.  
  40.     for(i=2; i<n; i++){
  41.         if(n%i==0){
  42.             sosuu = 0;
  43.             break;
  44.         }
  45.     }
  46.     return sosuu;
  47. }
Success #stdin #stdout 0s 5320KB
comments (?)
stdin 
24
stdout 
 1: 24 = 5 + 19
 2: 24 = 7 + 17
 3: 24 = 11 + 13
https://ideone.com/9LGKFm
language:
C (gcc 8.3)
created:
15 days ago
visibility:
public

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