shroomiin

Hey everyone. I have to write a program that estimates the value of mathematical constant e by using the following formula and i have to allow the user to enter the amount of terms to calculate. the only problem is i dont really know how to get started with this.

equation : e=1+1/1!+1/2!+1/3!...

i know that i am going to have to use a counter in this..to determine how many terms to calculate...would i create the counter and then ask the user to enter a value for counter? can you do that? i am just lost with this and if somebody could give me a push in the right direction i would appreciate it. Thanks!

First write a method that calculates the n!. Then use a for loop. How many times you will iterate it's up to you.
At the for loop you will use the classic algorithm for calculating sums. Declare a sum variable and add to it the result you get from inside the loop

shroomiin

sorry but could you please elaborate a little more? i am still confused on how to do it, so far i have this code which works and calculates n!. as for the for statement, where would i stick it? and whatvariables would i use in it?

``````import java.util.Scanner;
public class Factorials {

public static void main(String[] args) {

Scanner input = new Scanner(System.in);

int num;
int nFact;

num=input.nextInt();

nFact = fact(num);

System.out.println(num + "! = " + nFact + ".");
}
static int fact(int num){
if(num<=1)
return 1;

else{
return num*fact(num-1);
}

}
}``````

Sum = 1+2+3+ .... + i + ...
The pattern is
Sum = Σ(i)

``````int sum = 0;
for (int i=0;i<N;i++) {
sum += [B]i[/B]; // whatever is in the parenthesis Σ([B]i[/B])
}``````