Re: Missing return statement
Yuriy_Ivanov skrev:
package trianglecalculation;
import java.text.*;
import java.io.*;
import java.util.*;
/* This class uses ArrayList of triangular objects to
calculate their total area and perimeter.
*/
public class Main
{
/* this method is used to read in the object sides,
it needs additional validation */
public static double input (BufferedReader r, String prompt) throws
IOException
{
double side=0.0;
// handle the exceptions
try {
System.out.print( "Please enter " + prompt);
String myString = r.readLine();
side = Double.parseDouble(myString);
}
catch (NumberFormatException nfe)
{
System.out.println("Please enter a number!\n" + nfe);
}
return side;
} // end of input()
public static double main(String[] args) throws IOException // Array list
will be used instead of array?!
{
ArrayList aList = new ArrayList(); // Created with default size
(10).
Triangle ob = new Triangle(); // will be used as work object
int choice = 0; // for the user choice
double side1, side2, side3;
boolean exceptThrown = false; // if exception is thrown
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
do {
try {
System.out.print(" Please choose a triangular
object to add: ");
System.out.println( " 1: General; 2: Equilateral;
3: Right; 0: None ");
String myString = br.readLine(); //reads a line
(string) from the buffer br
//Parses the string argument
choice = Integer.parseInt(myString);
}
catch (NumberFormatException nfe)
{
exceptThrown = true;
System.out.println( "Please enter a number!\n" +
nfe);
}
switch (choice)
{
case 1: side1 = input(br, "side1: " );
side2 = input (br, "side2: " );
side3 = input (br, "side3: " );
Triangle tri = new Triangle(side1, side2, side3);
aList.add((Object) tri); //add to the list
break;
case 2: side1 = input(br, "side: ");
EquilateralTriangle equi = new
EquilateralTriangle(side1);
aList.add((Object) equi); //add to the list
break;
case 3: side1 = input(br, "side1: ");
side2 = input (br, "side2: ");
RightTriangle rig = new RightTriangle(side1,
side2);
aList.add((Object) rig); //add to the list
break;
case 0: break;
default: System.out.println( "\n Wrong choice!" );
exceptThrown = true;
}
} while (choice != 0 && !exceptThrown); //repeat the input
if (!exceptThrown) // will skip, if an exception was thrown
{
double totalA, totalP; // for the total area and
perimeter
System.out.println("\nObjects \t\t\t area \t\t
perimeter:");
// To accumulate the total area and perimeter
totalA = totalP =0.0;
/* In this loop each object from the array list will be
extracted and its name, area, and perimeter printed out. */
for(int i = 0; i < aList.size(); i++)
{
ob = (Triangle)aList.get(i); //casting to
Triangle
System.out.print (ob.displayName());
System.out.print ( "\t--> " + ob.area());
System.out.println ( " \t: " + ob.perimeter());
totalA += ob.area();
totalP += ob.perimeter();
}
/* if you would like to specify the number of fraction
digits,
use the NumberFormat abstract class. */
NumberFormat nf; // this is not an object
//Returns a general-purpose number format for the current
default locale
nf = NumberFormat.getNumberInstance();
nf.setMaximumFractionDigits(3); // to specify the number
of fraction digits
String areaTotal = nf.format(totalA); // convert to
String
String perimTotal = nf.format(totalP);
System.out.print("\nTotal area and perimeter are:");
System.out.println("\t\t" +areaTotal+ " :
"+perimTotal);
} // end if
} // end main - here it says there is a missing return statement
} // end class
I don't need there to be an else, nor do I need an "=" within the if, so
any ideas what I can do to fix this?
The main method is declared to return a double, that's why it needs a
return statement. Declare it void instead.
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