Please help with Java code

Question

How can I define a for loop for the following output:

1+2 = 3

2+3 = 5

4+5 = 9

8+9 = 17

16+17 = 33

32+33 = 65

64+65 = 129

any help would be very appreciated

Answer 1

Hi Fin.

Your question:

How can I define a for loop for the following output:

1+2 = 3

2+3 = 5

4+5 = 9

8+9 = 17

16+17 = 33

32+33 = 65

64+65 = 129

...is an interesting one.

I can see two sticking points:

1. the math that will give the desired output
2. the java for loop code

For the math, the first pattern I see is 1+2, 2+3, 4+5... which translates to:

x+x+1 or x*2+1

The second pattern I see is 1, 2, 4, 8, 16, 32, 64. That one translates to:

x*2 (with x starting at 1)

The first equation (x+x+1 or x*2+1, either one will work) is part of the content (code block) of your for loop, the second equation (x*2) is the increment to control the loop.

It's hard to write code in this answer box (it wants to handle the actual code), but I'll give it a try:

for (statement 1; statement 2; statement 3) {

// code block to be executed

}

So to begin defining your loop:

statement 1 should read something like int x=1 (you are to start with x equals 1)

statement 2 should read something like x<=64 (64 is where you stop)

statement 3 should read something like x=x+x or x=x*2 (your increment)

And your output statement needs to be a bit creative to get the proper formatting, something like:

System.out.print(x);

System.out.print(" + ");

System.out.print(x+1);

System.out.print(" = ");

System.out.println(x+x+1);

This is the straight forward, non-elegant approach, and you will have to complete the code. Elegance comes from combining steps into fewer lines of code.

Here are some links that can help:

https://www.geeksforgeeks.org/difference-between-print-and-println-in-java/

https://www.w3schools.com/java/java_for_loop.asp

https://www.geeksforgeeks.org/java-for-loop-with-examples/

and for a bit more elegance in your print()/println():

https://www.geeksforgeeks.org/java-for-loop-with-examples/

Happy coding!