#include <stdio.h>
//練習問題G
int func(int n){
int a, b=2, c=1;
int i;
if(n==1)
return 1;
else if(n==2)
return 2;
else
for(i=2;i<n;i++){
a = -2*b + 2*c;
}
return a;
}
int main(void) {
int n = 3;
printf("数列anについて, n=%dのときの値は%d\n", n
, func
(n
)); return 0;
}
I2luY2x1ZGUgPHN0ZGlvLmg+Ci8v57e057+S5ZWP6aGMRwoKaW50IGZ1bmMoaW50IG4pewogICAgaW50IGEsIGI9MiwgYz0xOwogICAgaW50IGk7CiAgIGlmKG49PTEpCiAgICByZXR1cm4gMTsKICAgZWxzZSBpZihuPT0yKQogICAgcmV0dXJuIDI7CiAgIGVsc2UgCiAgIGZvcihpPTI7aTxuO2krKyl7CiAgIAkgYSA9IC0yKmIgKyAyKmM7CiAgIH0KICAgICAgcmV0dXJuIGE7Cn0KaW50IG1haW4odm9pZCkgewoJaW50IG4gPSAzOwogICAgcHJpbnRmKCLmlbDliJdhbuOBq+OBpOOBhOOBpiwgbj0lZOOBruOBqOOBjeOBruWApOOBryVkXG4iLCBuLCBmdW5jKG4pKTsKCXJldHVybiAwOwp9Cg==