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  1.  
  2. #include <stdio.h>
  3. //練習問題G
  4.  
  5. int func(int n){
  6.     int a, b = 2, c = 1;
  7.     int i;
  8.  
  9.     if(n == 1){
  10.         return 1;
  11.     }
  12.     else if(n == 2){
  13.         return 2;
  14.     }
  15.  
  16.     for(i = 3; i <= n; i++){
  17.         a = -2 * b + 2 * c;
  18.         c = b;
  19.         b = a;
  20.     }
  21.  
  22.     return b;
  23. }
  24.  
  25. int main(void) {
  26.     int n = 3;
  27.     printf("数列anについて, n=%dのときの値は%d\n", n, func(n));
  28.     return 0;
  29. }
  30.  
Success #stdin #stdout 0.01s 5316KB
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Standard input is empty
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数列anについて, n=3のときの値は-2
https://ideone.com/X7vJ0s
language:
C (gcc 8.3)
created:
20 days ago
visibility:
public

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