ternary

[Joe Allen]

How to explain this statement:

System.out.println(true?false?"7":false?"6":false?true?"5": true?"4":"3":"2":"1");//prints "2"

[Saif Asif]

well lets break it down one by one .
Solve for the outer true first
This

true ? false ? "7" : false ? "6" : false ? true ? "5" : true ? "4" : "3" : "2": "1"

should now resolve to this

false ? "7" : false ? "6" : false ? true ? "5" : true ? "4" : "3" : "2"

Solving for the false now, it becomes.

false ? "6" : false ? true ? "5" : true ? "4" : "3" : "2"

Again solving for the false gives.

false ? true ? "5" : true ? "4" : "3" : "2"

Now we just have a single if-else block ( outer ) with the if condition as false. So we can just jump to the else part .

"2"

I hope I explained fine..

[Joe Allen]

Got it. Thank you very much.

[vishal mishra]

Not got it please explain it from following step

false ? true ? "5" : true ? "4" : "3" : "2":"1"

Why it is a single if-else block what about this-:

true ? "4" : "3" : "2":"1"

I am not getting what is happening here so please explain me too...

Thanks

[Saif Asif]

true ? "4" : "3" : "2":"1"

This is not a valid statement. Only one IF and 3 else blocks. ( note that I didnt say NESTED else-if blocks ). THe statement you wrote is similar to the following code snippet

if(true){
			//4
		}else{
			//3
		}else{
			//2
		}else{
			//1
		}

which is invalid.

Now the other statement

false ? true ? "5" : true ? "4" : "3" : "2" (there is no 1 in the end , it was solved by the previous step)

is equivalent to following code snippet

if(false){  //The outer IF which will result in false
			if(true){
				//5
				System.out.println("5");
			}else {
				if(true){
					//4
					System.out.println("4");
				}
			}
		}else{  //So this else block will execute.
			//2
			System.out.println("2");
		}

which will always result in 2. I hope I was clear in explaining it . Do post back for any further queries.

[vishal mishra]

Saif Asif wrote:

true ? "4" : "3" : "2":"1"

This is not a valid statement. Only one IF and 3 else blocks. ( note that I didnt say NESTED else-if blocks ). THe statement you wrote is similar to the following code snippet

if(true){
			//4
		}else{
			//3
		}else{
			//2
		}else{
			//1
		}

which is invalid.

Now the other statement

false ? true ? "5" : true ? "4" : "3" : "2" (there is no 1 in the end , it was solved by the previous step)

is equivalent to following code snippet

if(false){  //The outer IF which will result in false
			if(true){
				//5
				System.out.println("5");
			}else {
				if(true){
					//4
					System.out.println("4");
				}
			}
		}else{  //So this else block will execute.
			//2
			System.out.println("2");
		}

which will always result in 2. I hope I was clear in explaining it . Do post back for any further queries.

Thank you, this is crystal clear now, thanks a lot

[Joe Allen]

Saif Asif,
It is very nice and clear that you used that if-else to explain it. It seems like there is an "else System.out.println("3");" missing for the "if..." that prints out 4.
Thanks again.

[Saif Asif]

Saif Asif,
It is very nice and clear that you used that if-else to explain it. It seems like there is an "else System.out.println("3");" missing for the "if..." that prints out 4.
Thanks again.

Oh yes you are absolutely right , I corrected it as below. Thanks for pointing it out

if(false){  //The outer IF which will result in false  
            if(true){  
                //5  
                System.out.println("5");  
            }else {  
                if(true){  
                    //4  
                    System.out.println("4");  
                }else{
                    System.out.println("3"); 
                }  
            }  
        }else{  //So this else block will execute.  
            //2  
            System.out.println("2");  
        }  

[Dan Drillich]

Vishal,

It's much simpler because we simply get the outer 2. We never get to execute the inner statement. If we did we would get 5 (true ? "5": true ? "4": "3").

Saif Asif wrote:

false ? true ? "5" : true ? "4" : "3" : "2"

Now we just have a single if-else block ( outer ) with the if condition as false. So we can just jump to the else part .

"2"

I hope I explained fine..

Regards,
Dan