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  1. #include <stdio.h>
  2.  
  3. int rec(int n){
  4.     if(n <= 0){
  5.         return 0;
  6.     }
  7.     return n + rec(n - 2);
  8. }
  9.  
  10. int main(void) {
  11.     int n = 6;
  12.     int tmp = n;   // 表示用にコピー
  13.  
  14.     printf("rec(%d) = ", n);
  15.  
  16.     // 表示用ループ
  17.     for(tmp; tmp > 0; tmp -= 2){
  18.         printf("%d+", tmp);
  19.     }
  20.  
  21.     // 計算は元の n を使う
  22.     printf("=%d\n", rec(n));
  23.  
  24.     return 0;
  25. }
  26.  
Success #stdin #stdout 0s 5320KB
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Standard input is empty
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rec(6) = 6+4+2+=12
https://ideone.com/g82dad
language:
C (gcc 8.3)
created:
5 days ago
visibility:
public

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