JAVA program to find sum of elements in an array
This JAVA program is to find sum of elements in an array.
For example, if my array contains 4 elements let us say these elements are {9, 12 , 13, 6} then their sum would be 40.
Logic
We use a for loop and keep adding elements till we reach n.
Dry Run of the Program
Let us take number of elements n. Let us take n=3
Then run a for loop for n(3) elements and store it inside array ‘a’.
Let us take an input array ‘a’. Let us take elements for array a={7,12,21}
1st iteration for(i=0;i<n;i++) i.e. for(i=0;i<3;i++)
sum=sum+a[i]; i.e. sum=0+a[0]; i.e. sum=0+7; i.e. sum=7
2nd iteration for(i=0;i<n;i++) i.e. for(i=1;i<3;i++)
sum=sum+a[i]; i.e. sum=7+a[1]; i.e. sum=7+12; i.e. sum=19
1st iteration for(i=0;i<n;i++) i.e. for(i=2;i<3;i++)
sum=sum+a[i]; i.e. sum=19+a[2]; i.e. sum=19+21; i.e. sum=40
After this you come out of the for loop as i is not less than 3( i(3) < 3)
Hence sum=40.
Program
import java.util.*; class arr1 { public static void main(String args[]) { Scanner sc = new Scanner(System.in); int i,n,sum=0; System.out.println("Enter the number of elements:") ; n = sc.nextInt(); int[] a = new int[n]; System.out.println("Enter the elements") ; for(i=0;i<n;i++) { a[i] = sc.nextInt(); } for(i=0;i<n;i++) { sum=sum+a[i]; } System.out.println("Sum of "+n+" elements in an array = "+sum); } }