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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.  
  8.     if(n == 1){
  9.         return c;
  10.     } else if(n == 2){
  11.         return b;
  12.     } else {
  13.         for(i = 3; i <= n; i++){
  14.             a = 2 * c - 2 * b;  
  15.             c = b;             
  16.             b = a;
  17.         }
  18.         return a;
  19.     }
  20.  
  21.  
  22. }
  23. int main(void) {
  24. 	int n = 3;
  25.     printf("数列anについて, n=%dのときの値は%d\n", n, func(n));
  26. 	return 0;
  27. }
  28.  
Success #stdin #stdout 0s 5320KB
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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/AYyzwq
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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