更真實模型:軟工年薪 40 萬存銀行定存年息 3.5%,房價 187 萬(首付?)年漲 10%。每年:存款 = 存款×1.035 + 40;房價 ×=1.1。比較何時存款 ≥ 房價。
S_n = S_{n-1} * 1.035 + 40,S_0 = 40 * 1.035。H_n = H_{n-1} * 1.1,H_0 = 187 * 1.1。#include <stdio.h>
int main() {
int i=0;
float salary=40, house=187, rate=0.1, bank_rate=0.035, savings=0;
house = house * (1+rate);
savings = salary * (1+bank_rate);
while (savings < house) {
i++;
house *= (1+rate);
savings = savings * (1+bank_rate) + salary;
}
printf("存銀行後,經過%d年可買房!\n", i);
return 0;
}

銀行利息 3.5% 遠低於房價漲幅 10%,儲蓄增速依然跟不上房價,買房難度未本質改善。