Question

Write a Java program to print the above pattern till “n” numbers.

Answer 1

$\bf\huge\underline{Answer}:-$

Here we need to find the sum and factorial of a number by using Scanner class.

Program Códe :

import java.util.*;

class series

{

public static void main(String args[])

{

Scanner sc = new Scanner(System.in);

System.out.println("Enter term no")

int n = sc.nextInt();

double sum = 0.0;

for (int i = 2; i<=n; i++)

{

int s = 0, f = 1;

for(int j = 1; j<=i; j++)

{

s = s + j;

f = f * j;

}

sum = sum + (double) s/f;

}

System.out.println("Sum of the series="+sum)

}

}

Output :

Enter term no

3

Sum of the series=2.5

Working :

Let's take the term no as 3.

The i loop is starting from 2 therefore, the i loop will run only 2 times.

1st Iteration :

i = 2 and n = 3

Inside the j loop,

j = 1 and i = 2

• s = s + j = 0 + 1 = 1
• s = s + j = 1 + 2 = 3

• f = f * j = 1 * 1 = 1
• f = f * j = 1 * 2 = 2

• sum = sum + s/f = 0.0 + 3/2 = 1.5

2nd Iteration :

i = 3 and n = 3

Inside the j loop,

j = 1 and i = 3

• s = s + j = 0 + 1 = 1
• s = s + j = 1 + 2 = 3
• s = s + j = 1 + 2 + 3 = 6

• f = f * j = 1 * 1 = 1
• f = f * j = 1 * 2 = 2
• f = f * j = 1 * 2 * 3 = 6

• sum = sum + s/f = 0.0 + 6/6 = 1.0

Final sum = 1.5 + 2.0 = 2.5

For better understanding refer to the attachment.