Refactoring Notes-Refactoring Methods

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1.Extract Method
Turn the fragment into a method whose name explains the purpose of the method.
Before:
void printOwing(){
    Enumeration e =orders.elements();
    double outstanding=0;

    //print banner
    System.out.println("*******************");
    System.out.println("***Customer Owes***");
    System.out.println("*******************");

    //calculate outstanding
    while(e.hasMoreElements()){
        Order each=(Order)e.nextElement();
        outstanding+=each.getAmount();
    }

//    print details
    System.out.println("name: "+name);
    System.out.println("amount "+amount);
}

After:
void printOwing(double amount){
printBanner();
amount=getOutstanding();
printDetails(amount);
}

void printBanner(){
  System.out.println("*******************");
    System.out.println("***Customer Owes***");
    System.out.println("*******************");
}

void printDetails(double amount){
System.out.println(“name” + name);
System.out.println(“amount”+amount);
}

double getOutstanding(){
Enumeration e =orders.elements();
double result=0.0;
while(e.hasMoreElements()){
          Order each=(Order)e.nextElement();
          result+=each.getAmount();
}
return result;
    }
}