20 【程式 20 求前 20 項之和】
題目:有一分數序列:2/1,3/2,5/3,8/5,13/8,21/13...求出這個數列的前 20 項之和。
package cskaoyan;
public class cskaoyan20 {
@org.junit.Test
public void sum() {
double numerator = 2;
double denominator = 1;
double total = 0;
for (int i = 0; i < 20; i++) {
total += numerator / denominator;
double temp = numerator;
numerator = numerator + denominator;
denominator = temp;
}
System.out.println("這個數列的前 20 項之和是" + total);
}
}