actual and formal argument lists differ in length error

Question

I'm currently working on a program that tells you what type of triangle the user has inputted, the perimeter and area. I'm currently receiving the error "actual and formal argument lists differ in length", and I have tried Googling a solution, but I am not too sure what is causing that error.

import java.util.*;

public class TriangleTesterID8876 {
  public static void main(String[] args) {
    Triangle userTriangle = new Triangle();
    Scanner kb = new Scanner(System.in);

    System.out.println("==================================");
    System.out.println("  This program is designed for");
    System.out.println("  the user to input a triangle");
    System.out.println("     and calculate the area, ");
    System.out.println(" perimeter, and type of triangle");
    System.out.println("==================================");

    //Side 1
    System.out.println("Please input the first side.");
    double side1 = kb.nextDouble();
    userTriangle.setSide1(side1);

    //Side 2
    System.out.println("Please input the second side.");
    double side2 = kb.nextDouble();
    userTriangle.setSide2(side2);

    //Side 3 
    System.out.println("Please input the third side.");
    double side3 = kb.nextDouble();
    userTriangle.setSide3(side3);

    System.out.println(userTriangle.typeString());
  }
}

Triangle.java:

public class Triangle {
  private double mySide1;
  private double mySide2;
  private double mySide3;

  public String backHalf;


  public void setSide1(double side1) {
    mySide1 = side1;
  }

  public void setSide2(double side2) {
    mySide2 = side2;
  }

  public void setSide3(double side3) {
    mySide3 = side3;
  }

  public double getSide1() {
    return mySide1;
  }

  public double getSide2() {
    return mySide2;
  }

  public double getSide3() {
    return mySide3;
  }

  private boolean isValid() {
    if ((mySide1 < mySide2 + mySide3) && (mySide2 < mySide1 + mySide3) && (mySide3 < mySide1 + mySide2)) {
      return true;
    } else
      return false;
  }

  public boolean isEquilateral() {
    if ((mySide1 == mySide2) && (mySide2 == mySide3)) {
      return true;
    } else {
      return false;
    }
  }

  public boolean isIsoscelese() {
    if (mySide1 == mySide2 || mySide1 == mySide3 || mySide1 == mySide2) {
      return true;
    } else {
      return false;
    }
  }

  public boolean isScalene() {
    if (mySide1 != mySide2 && mySide2 != mySide1 && mySide2 != mySide3) {
      return true;
    } else {
      return false;
    }
  }

  public double perimeter() {
    return mySide1 + mySide2 + mySide3;
  }

  public double findArea() {
    double s = perimeter() / 2;
    return Math.sqrt(s * ((s - mySide1) * (s - mySide2) * (s - mySide3)));
  }

  public String toTypeString() {
    double perimeter = perimeter();
    double area = findArea();

    backHalf = mySide1 + " " + mySide2 + " " + mySide3 + ", a perimeter of " + perimeter + ", and an area of " + area + ".";
    return backHalf;

  }

  public String typeString(String output) {
    if (isValid() == true) {
      if (isEquilateral()) {
        output = "This is an equilateral triangle with sides " + backHalf;
        return output;
      } else if (isIsoscelese()) {
        output = "This is an isosceles triangle with sides " + backHalf;
        return output;
      } else if (isScalene()) {
        output = "This is a scalene triangle with sides " + backHalf;
        return output;
      }
    } else
      output = "Please input a valid triangle.";
    return output;

  }
}

Isn't your compiler telling you where these problems are happening? — mkobit, Oct 20 '14 at 03:45
I'm not sure why you were using code snippets with `lang-js`, but Java Is Not JavaScript. — Chris Hayes, Oct 20 '14 at 03:46

score 4 · Accepted Answer · answered Oct 20 '14 at 03:45

You declared typeString() with a single String parameter but you are calling it - userTriangle.typeString() - without any parameter.

It looks like you should remove that parameter :

change :

public String typeString(String output) {

to

public String typeString() {
    String output = null;
    ....
}

score 0 · Answer 2 · answered Oct 20 '14 at 03:47

0

typeString() takes in a string as a parameter. In your case, you are calling it empty

answered Oct 20 '14 at 03:47

Victor2748

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score 0 · Answer 3 · answered Oct 20 '14 at 03:53

Your Triangle class says that typeString(String output) should have an argument but you used like this without parameter.

System.out.println(userTriangle.typeString());

Either use

System.out.println(userTriangle.typeString());

as

System.out.println(userTriangle.typeString(output));

OR

Change your Triangle class method signature typeString(String output) to typeString().

actual and formal argument lists differ in length error

3 Answers3