Java Programming - Flow Control - Discussion

Discussion Forum : Flow Control - Finding the output (Q.No. 15)
15.
What will be the output of the program?
public class Delta 
{ 
    static boolean foo(char c) 
    {
        System.out.print(c); 
        return true; 
    } 
    public static void main( String[] argv ) 
    {
        int i = 0; 
        for (foo('A'); foo('B') && (i < 2); foo('C')) 
        {
            i++; 
            foo('D'); 
        } 
    } 
}
ABDCBDCB
ABCDABCD
Compilation fails.
An exception is thrown at runtime.
Answer: Option
Explanation:

'A' is only printed once at the very start as it is in the initialisation section of the for loop. The loop will only initialise that once.

'B' is printed as it is part of the test carried out in order to run the loop.

'D' is printed as it is in the loop.

'C' is printed as it is in the increment section of the loop and will 'increment' only at the end of each loop. Here ends the first loop. Again 'B' is printed as part of the loop test.

'D' is printed as it is in the loop.

'C' is printed as it 'increments' at the end of each loop.

Again 'B' is printed as part of the loop test. At this point the test fails because the other part of the test (i < 2) is no longer true. i has been increased in value by 1 for each loop with the line: i++;

This results in a printout of ABDCBDCB

Discussion:
15 comments Page 2 of 2.

Gaurav said:   1 decade ago
How can D print after B.

And again after D it print C.

Can any one explain this process?

Sahil said:   1 decade ago
Try to run this code, it will neither produce any output nor throws exception...

Madhu said:   1 decade ago
The code is perfect and produces the output as mentioned in option A.

Rupesh singh said:   8 years ago
Please anyone explain me clearly to get it.

Ami said:   8 years ago
Can anyone explain in detail?


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