Reputation: 35

Please explain this specific line in my Java Code?

I have just started learning Java and I reached till arrays , I was preparing this program(From a book) on replacing space ' ' with '.' (dots) and i am not able to understand this specific line (its not mentioned even in the book I am learning from).

Please help me out.

class SpaceRemover{
    public static void main(String[] args){
        String mostFamous = "Hey there stackoverFLow     ";
        char [] mf1 = mostFamous.toCharArray();
        for(int dex = 0; dex<mf1.length;dex++)
        {
            char current = mf1[dex];   // What is happening in this line ??
            if (current != ' ') {
                System.out.print(current);

            }
            else{
                System.out.print('.');

            }
        }
        System.out.println();


        }
    }

Someone please explain what is happening in "char current = mf1[dex];"

Thanks a lot for your time.

Upvotes: 1

Answers (10)

kamo_7

Reputation: 46

Basically a String in java is an array of characters. So what the above code does is converts the string to an array of chars so that it can access each index of the array later on. Then the code enters into a for loop in order to iterate through all the indecies of the char array.

Assuming that that is already clear to you, the code now creates a char variable which holds the current index of the array.

char current = mf1[dex];

mf1 is your char array that represents the string. dex is the current index of the char that is determined by the for loop. So by doing this we can check each character (letter) of the char array. Now if the char "current" is a blank space we can replace it with a dot.

Upvotes: 1

passion

Reputation: 44

After this statement, char [] mf1 = mostFamous.toCharArray();

mf1[0]=H, mf1[1]=e, mf1[1]=y...

so at this line, char current = mf1[dex]; so, in first iteration, current=H, second iteration current=e...

Upvotes: 0

Jeremy Zhou

Reputation: 49

char current = mf1[dex];

this will return the char element in char array whose index is dex

This is quite a basic usage of array.

Good luck with your study.

Upvotes: 0

Bohemian

Reputation: 425238

It assigns the element of the char array mf1 at the index dex to the char variable current.

Note that the for loop and that line may be simplified by using the foreach syntax; these two code blocks are equivalent:

// Your code
for(int dex = 0; dex<mf1.length;dex++) {
    char current = mf1[dex]; 

// Equivalent code
for (char current : mf1) {

But further, the whole method may be replaced by one line:

public static void main(String[] args){
    System.out.println("Hey there stackoverFLow     ".replace(" ", "."));
}

Upvotes: 0

Ganesh Joshi

Reputation: 155

Here is solution

class SpaceRemover{

    public static void main(String[] args){

        String mostFamous = "Hey there stackoverFLow     ";

            char [] mf1 = mostFamous.toCharArray();

            // mf1 contains={'H', 'e','y',' ','t','h',.........}

            for(char current: mf1)

            {

         //the for-each loop assigns the value of mf1 variable to the current variable

                //At first time the 'H' is assigned to the current and so-on

                System.out.print(current==' '?'.':current );

            }

            System.out.println();



            }

        }
    }

Upvotes: 0

tuzhucheng

Reputation: 178

The line

char current = mf1[dex];

is placed inside a for loop where the variable dex is incremented each time the loop is iterated. The variable dex is the zero-based index of the array. On the left hand side of the assignment operator (=), you are declaring a variable named current of type char. On the right hand side of the assignment operator you are accessing the dex-th character of your CharArray, if you start counting from zero. The assignment operator binds the variable you declared with the value of the character you specified on the right hand side.

For example, the first time the loop is run, dex would start at 0, hence mf1[dex] (or mf1[0]) is just 'H'.

Upvotes: 0

Chathura Priyankara

Reputation: 73

char current = mf1[dex];

This line gets values from the mf1 char array and assign to the current variable according to the dex, dex works as index to the array element and it increments with the running loop.

Upvotes: 0