text: Sum of Fibonacci Numbers with alternate negatives | Java Program to find alternate sum of Fibonacci numbers ; Computes value of first fibonacci numbers and stores their alternate sum ; Initialize result ; Add remaining terms ; For even terms ; For odd terms ; Return the alternating sum ; Driver code ; Get n ; Find the alternating sum
code: public class GFG { static double calculateAlternateSum ( int n ) { if ( n <= 0 ) return 0 ; int fibo [ ] = new int [ n + 1 ] ; fibo [ 0 ] = 0 ; fibo [ 1 ] = 1 ; double sum = Math . pow ( fibo [ 0 ] , 2 ) + Math . pow ( fibo [ 1 ] , 2 ) ; for ( int i = 2 ; i <= n ; i ++ ) { fibo [ i ] = fibo [ i - 1 ] + fibo [ i - 2 ] ; if ( i % 2 == 0 ) sum -= fibo [ i ] ; else sum += fibo [ i ] ; } return sum ; } public static void main ( String args [ ] ) { int n = 8 ; System . out . println ( " Alternating ▁ Fibonacci ▁ Sum ▁ upto ▁ " + n + " ▁ terms : ▁ " + calculateAlternateSum ( n ) ) ; } }