Java understanding For loops

1

I just learnt about Looping, Pre and Post increment, but I think I didn’t understand it.
Can someone explain this code loop by loop. Thanks in advance.

class Multi
{
 public static void main(String[] args)
 {
  for(int x = 0; x < 4; x++)
  {
    for(int y = 4; y > 2; y--)
     {
        System.out.println(x + " " + y);
     }
     if(x == 1)
     {
        x++;
      }
 }
} }

the output for the above code is :
0 4
0 3
1 4
1 3
3 4
3 3
When I tried to find the output I got confused in the second iteration when x value is equal to 1 and it’s incremented to 2 I think.So I looked into the solution and pasted above.

2 
  for(int x = 0; x < 4; x++) {

This for statement, the outer loop

  • initializes x to 0
  • checks that x < 4,
  • and increments x by one after each iteration of the loop body
    for(int y = 4; y > 2; y--) {
        System.out.println(x + " " + y);
     }

The inner loop

  • initializes y to 4
  • checks that y < 2
  • and decrements y by one after each iteration of the loop body
     if (x == 1) {
        x++;
     }

This if statement checks if x has the value 1. If it does, the x value is incremented by 1. It is within the body of the first for loop, and it is executed before the loop’s first statement for(int x = 0; x < 4; x++) increments x. The effect in your example is that the inner loop (with your print statement) is effectively skipped when x == 2.
In other words, when x == 1, the flow is like

  • check if x < 4 (true)
  • execute loop body
    • execute inner loop
    • check if x == 1 (true)
      • increment x (x is now 2)
  • increment x (x is now 3)
  • check if x < 4 (true)
    etc
3

o=outer, i=inner
loop x y comments
o1 i1 0 4
o1 i2 0 3
o2 i1 1 4
o2 i2 1 3
o3 i1 3 4 x incremented twice
o3 i2 3 3

X is incremented twice because there are two incremental operators during completion of 4 th iteration of the combined for loops.