#include <iostream>
#include <cmath>
using namespace std;

int main() {
	long long whole, each, months;
	cin >> whole >> each >> months;
	double rate = 0.0;
	double last_difference = 10000000000000000000000000000000.0;
	while (true) {
		double temp_whole = whole;
		for (long long i = 0; i < months; i++) {
			temp_whole -= (each - temp_whole*rate);
		}
		cout << "RATE: " << rate << " Whole: " << temp_whole << endl;
		if (fabs(temp_whole) > fabs(last_difference)) {
			printf("%.1f", (rate - 0.001) * 100);
			break;
		}

		last_difference = temp_whole;
		rate += 0.001;
	}
}

这段代码就是通过暴力迭代，检验哪个利率最合理，然后退出循环；不知道为什么在#4、%5上栽了跟头，程序直接返回0.0

急切求助