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  1. #include <stdio.h>
  2.  
  3.  
  4. int func(int n){
  5.     int a, b=2, c=1;
  6.     int i;
  7. if(n == 1){
  8.         return c;
  9.     } else if(n == 2){
  10.         return b;
  11.     } else {
  12.         for(i = 3; i <= n; i++){
  13.             a = 2 * c - 2 * b;  
  14.             c = b;              
  15.             b = a;
  16.         }
  17.         return a;
  18.     }
  19.  
  20. }
  21. int main(void) {
  22. 	int n = 3;
  23.     printf("数列anについて, n=%dのときの値は%d\n", n, func(n));
  24. 	return 0;
  25. }
Success #stdin #stdout 0s 5324KB
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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/tC7g9V
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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