程序代码：

#include <stdio.h>
#define M 10
#include <math.h>
int main() {

  double s = 0, i = 3, j, s1, s2, s3 = 0, a, b, c, d;
  scanf("%lf", &j);
  for (i = 1; i <= j; i++) {
/*************************************/
// i 一直是 1, 进入死循环了
    while (i == 1) {
      s1 = (i + 1) / i; // s1=2/1,a=2,b=1
      a = i + 1;
      b = i;
    }
/*************************************/
    while (i == 2) {
      s2 = s1 + (i + 1) / i; // s2=3/2;c=3,d=2
      c = i + 1;
      d = i;
    }
    s = s2 + (a + c) / (b + d); // s=s2+(2+3)/(1+4),a=5,b=3
    a = (a + c);
    b = (b + d);
    s3 = s + (a + c) / (b + d); // s3=s+(5+3)/(3+2),c=8,d=5
    c = a + c;
    d = b + d;
  }
  printf("%lf", s); //求第二十项
  return 0;
}

[此贴子已经被作者于2023-10-2 21:23编辑过]

程序代码：

#include <stdio.h>

#define M 100

int main(void) {
    int a[M], b[M];
    int n;
    double total = 0.0;
    a[0] = 2;
    a[1] = 3;
    b[0] = 1;
    b[1] = 2;

    scanf("%d", &n);
    for(int i=2; i<n; ++i) { // 填充数组
        a[i] = a[i-1] + a[i-2];
        b[i] = b[i-1] + b[i-2];
    }

    for(int i=0; i<n; ++i) {
        total += 1.0 * a[i] / b[i];
    }

    printf("total = %lf\n", total);
    return 0;
}

[此贴子已经被作者于2023-10-2 21:54编辑过]