Running of code for triangle after user input

im doing an assignment and would require to user to input 3 number int 1-9 and then determine if it is a triangle

• (a=4, b=5, c=6 is a triangle)
• (a=1, b=2, c=2 is not a triangle)

and from there determine if it is an

1. Equilateral (3 sides are equal)
2. Isosceles (2 side are equal)
3. Scalene (3 sides are different)
4. NotTriangle

the code i've done so far has some troubles running them which i cant seem to identify where is the problem. it keeps coming out with errors from the sub class method named displayInfo which links via method isTriangle2 & getType to determine both if it is a triangle and which type if it is.

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
The method printf(String, Object...) in the type PrintStream is not applicable for the arguments (String, void)

at PossibleTriangle.displayInfo(Test.java:187)
at Test.main(Test.java:225)

here is my full code for reference:

import java.util.Scanner;

enum Type {EQUILATERAL, ISOSCELES, SCALENE, NOTTRIANGLE}

// S T A R T   T R I A N G L E   C L A S S

class PossibleTriangle
{
	// Declare instance variables related to Health Profile
	private int a;
	private int b;
	private int c;
	private Type pt;
	
	// Default Constructor
	public PossibleTriangle ()
	{
		//by default	
	}
	
	// Other Constructor
	public PossibleTriangle  (int a, int b, int c)
	{
		this.a = a;
		this.b = b;
		this.c = c;
	}
	
	
	// Copy Constructor
	public PossibleTriangle (PossibleTriangle p)
	{
		this(p.a, p.b, p.c);
	}

	// Accessor Methods
	
	public int getA ()
	{
		return a;
	}
	
	public int getB ()
	{
		return b;
	}
	
	public int getc ()
	{
		return c;
	}
	
	public Type getPt ()
	{
		return pt;
	}
	
	// Mutator Methods
	public void setInfo (int a, int b, int c, Type pt)
	{
		this.a = a;
		this.b = b;
		this.c = c;
		this.pt = pt;
	}
	
	
	private boolean isTriangle (int a, int b, int c)
	{	
		if ((a + b <= c) || (a + c <= b) || (b + c <= a))
			return true;
		
		else 	
			return false;
	}
	
	private void isTriangle2 (int a, int b, int c)
	{
		
		if ((isTriangle(a,b,c)) == true)
            System.out.printf("Valid Triangle%n"); 
        else
            System.out.printf("Not a Triangle%n"); 
	}
	

	private static Type getType2 (int a, int b, int c, Type pt)
	{
		// Divide character set into four types
		if ((a == b) && (b == c) && (c == a)) {
			return Type.EQUILATERAL;
			
		} else if ((a == b && b != c) || (a != b && c == a) || (c==b && c != a)) {
			return  Type.ISOSCELES;
			
		} else if ((a != b) && (b != c) && (c != a)) {
			return  Type.SCALENE;
			
		} else {
			return  Type.NOTTRIANGLE;
		}
	}

	
	private void getType (Type pt)
	{		
		
		switch (pt){
		
		case EQUILATERAL: System.out.printf("Equilateral Triangle");
						  		break;
						  
		case ISOSCELES:	  System.out.printf("Isosceles Triangle");
								break;
        
		case SCALENE:	  System.out.printf("Scalene Triangle");
						  		break;

		default:		  System.out.printf("Not a triangle");
								break;
					}
	}
	
	// Display method
	public void displayInfo ()
	{		
		PossibleTriangle t = new PossibleTriangle (a, b, c);
		
		System.out.printf ("\tCharacter is %n. Its type is " , this.getType(pt));
	}

}   
// E N D   T R I A N G L E   C L A S S



// S T A R T   M A I N   C L A S S    
class Test
{	
	public static void main (String[] args) 
	{	
		
		Scanner input = new Scanner (System.in);
		
		int a;
		int b;
		int c;
		Type pt;
		
		// READ FIRST TRIANGLE
		
		System.out.printf ("Enter 3 numbers: ");
		a = input.next ().charAt (0);
			
		b = input.next ().charAt (0);
			
		c = input.next ().charAt (0);
	
		
		PossibleTriangle p = new PossibleTriangle (a, b, c);
		p.displayInfo();


		// READ SECOND TRIANGLE
		
		System.out.printf ("%nEnter 3 numbers: ");
		a = input.next ().charAt (0);
			
		b = input.next ().charAt (0);
			
		c = input.next ().charAt (0);

	
	}
}

It is difficult to find out what your assignment is by reading your description, but it seems that you need to write two methods:

• A method Type getType(int a, int b, int c) which returns the type of the triangle given the parameters a, b and c. This method would use an if-else statement.

• A method which displays the type given a Type object. This method would use a switch statement.

It will look something like this:

private static Type getType(int a, int b, int c) {
    if ( /* condition 1 */ ) {
        return NOTTRIANGLE;
    } else if ...
        ...
        ...
}

private static void displayAnalysis() {
    int a = /* ... */ ;
    int b = /* ... */ ;
    int c = /* ... */ ;
    Type type = getType(a, b, c); // <-- here getType is called to determine the type
    switch (type) {
        case NOTTRIANGLE:
            ...
            break;
        case EQUILATERAL;
            ...
            break;
        ...
        ...
    }
}

Note that the conditions in an if-else statement and checked in order, and that the rest of the conditions is not checked as soon as one conditions is satisfied. So, you need to think about in what order to check for the different types of triangle.

I don't think that this solution is the best.
First of all, we have to understand how the switch works (read the Oracle switch page). Look at this image:

Every case statement is indipendent, so you can't use if...else accross the switch case.
The correct form is:

switch (Type){

    case CASE1: //op1;
                break;
                 
    case CASE2: //op2;
                break;
            
    	[ . . . ]
            
    case CASE N: //opN;
                 break;

}//switch

Note that we have to write break; at the end of every block.

When you use a switch you are already doing a job similar to an if-else, so you should not use the switch to do other checks of this type.
You, probably, have to save the current Type in a variable (depending from the conditions) and use the switch to indicate what operations to perform.

For example:

enum Type {EQUILATERAL, ISOSCELES, SCALENE, NOTTRIANGLE}

/*
 int a = ...
 int b = ...
 int c = ...
*/

Type currentType = EQUILATERAL;

/*Now check the type of the triangle... I don't want to change your code, 
 but there are some errors in the conditions (the second "else" must be
 written before the first else...)
*/
if ((a + b <= c) || (a + c <= b) || (b + c <= a)) {
	currentType=NOTTRIANGLE;
} else if ((a == b) || (b == c) || (c == a)) {
	currentType=ISOSCELES;
} else if ((a == b) && (b == c) && (c == a)) {
	currentType=EQUILATERAL;
} else {
	currentType=SCALENE
}

//Now you can use the switch


switch (currentType){

case NOTTRIANGLE: 	System.out.printf("Not a triangle");
					//other operations
                  	break;
             
case ISOSCELES: 	System.out.printf("Isosceles Triangle");
					//other operations
                	break;   
        
case EQUILATERAL:   System.out.printf("Equilateral Triangle");
					//other operations
                	break;

default: 	System.out.printf("Scalene Triangle");
			//other operations
            break;
}

You can, obviously, put the if-else statement and the switch in different methods and call it from the main method.

If you want to get the 3 numbers as a user input, you can use java.util.Scanner; and its method nextInt(), that allows to read a number digited by the user.

Here's the code:

Scanner sc = new Scanner(System.in);
System.out.print("Enter A: ");
int a = sc.nextInt();
System.out.print("Enter B: ");
int b = sc.nextInt(); 
System.out.print("Enter C: ");
int c = sc.nextInt();