2. 有一数列：2/1，3/2，5/3，8/5，…求出这个数列的前 20 项之和。用c语言编程

以下是用 C 语言编写的求解该数列前20项之和的程序：

#include <stdio.h>

int main() {
    double numerator = 2, denominator = 1, sum = 0, temp;
    int i;

    for (i = 1; i <= 20; i++) {
        sum += numerator / denominator;
        temp = numerator + denominator;
        denominator = numerator;
        numerator = temp;
    }

    printf("The sum of the first 20 terms of the sequence is: %.2f\n", sum);
    return 0;
}

程序输出：

The sum of the first 20 terms of the sequence is: 32.66