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  1. #include <stdio.h>
  2. //練習問題G
  3.  
  4. int func(int n){
  5.     int a = 1, b = 2, c;  // a=a1, b=a2
  6.     int i;
  7.     if (n==1) return a;
  8.     else if (n == 2) return b;
  9. 	else{
  10.     for (i=3;i<=n;i++){
  11.         c=-2*b+2*a;
  12.         a=b;
  13.         b=c;
  14.     }
  15.     return c;
  16. 	}
  17. }
  18. int main(void) {
  19. 	int n = 3;
  20.     printf("数列anについて, n=%dのときの値は%d\n", n, func(n));
  21. 	return 0;
  22. }
  23.  
Success #stdin #stdout 0.01s 5288KB
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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-4
https://ideone.com/oqchOU
language:
C (gcc 8.3)
created:
18 days ago
visibility:
public

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