private double METHOD_1 ( double n ) { int i = 0 ; double sum = 1 ; for ( i = 1 ; i <= n ; i ++ ) { sum = sum * i ; } return sum ; } 

public double METHOD_1 ( double n ) { int i = 0 ; double sum = 1 ; for ( i = 1 ; i <= n ; i ++ ) { sum = sum * i ; } return sum ; } 
