Doesn't enter in the "for-loop"?

Question

Here is my code :

private String SerialNo;
private String FirmVersion;


public String  GetSerial(int[] Data){

    System.out.println("GetSerial Debug : Data => "+Data);

    for (int i = 2;i==13;i++){
        System.out.println("In the FOR => ok ");
        if (i != 9){
            SerialNo = SerialNo + Data[i];  
        }
        if (i == 9){
            SerialNo = SerialNo + ".";
        }
    }

    System.out.println("SerialNo => "+ SerialNo);
    return SerialNo;
}

My problem : I can't "enter" in the FOR

So my sysout of "In the FOR => ok", never shows and all the "actions" aren't done.

What am I doing wrong ?

ps : I'm sure that I'm compiling the right file.

Answer 1

Examine your for statement:

for (int i = 2; i==13; i++)

This actually means the following:

1. assign 2 to i
2. Check whether i equal to 13. If yes, continue loop, exit otherwise.

Since i is not 13 in the first iteration of loop you never enter it. I believe that you wanted to write

for (int i = 2; i <= 13; i++)

In this case you will iterate from 2 to 13 inclusively. The condition of for loop means "do I have to remain iterating?" and not "do I have to escape?"

Answer 2

The loop condition is never satisfied; i = 2 in the begin, the first check would fail, so all the loop would fail. Maybe it should be changed for:

for (int i = 2; i <= 13; ++i)

Answer 3

Change for (int i = 2; i == 13; i++) to for (int i = 2; i <= 13; i++).

The second argument is the loop condition which has to be true to run the loop.

Answer 4

Your condition became false at first iteration so control never goes to loop body.

for loop syntax:

for(initialization; condition; increment/ decrement){
  //your code
}

So here you will have to use some appropriate condition to enter into the loop.

So for example :

for (int i = 0; i <= 13; i++) // for 0 to 13 increment

or

for (int i = 10; i >= 0; i--) // for 10 to 0 decrement

Answer 5

for (int i = 2;i==13;i++){}

It enters but failed at first condition check and for-loop exits.

It should be -

for (int i = 2;i<=13;i++)

Answer 6

You have initialized i=2

 for (int i = 2;i==13;i++)

And condition is i==13 which will become false ultimately flow never enter into for loop

try to change the code like this

for (int i = 2;i<=13;i++)

Answer 7

Statement is not good should be like the one below:

for (int i = 2; i<13; i++) or for (int i = 2; i<=13; i++)

Answer 8

See compared simple while loop in the case of your for loop.

Think about int i =2; value set and i == 13 condition

1. Do you think it will work?

   for (int i = 2;i==13;i++){
     //do something
   }
   
   Same to below *while loop* explanation
   
   int i = 2;
   while (i == 13) {
       //do something
       i++;
   }
   

2. I am sure it will work

   for (int i = 2;i < 13;i++){
      //do something
   }
   
   Same to below **while loop**
   
   int i = 2;
   while (i < 13) {
       //do something
       i++;
   }
   

Answer 9

The flow of the for loop is: init statement-> condition check-> goes inside loop or outside depending on the condition outcome.

Here, since you've said i=2 ,then i==13 is false; it'll never go inside the loop. You could use the ?: operator in the for loop and then modify your if statements a bit I guess..