CODEWITHSUNDEEP
java
anthonydoesntknowhowtocode
anthonydoesntknowhowtocode

Reputation: 75

How to fix loop so that the code does not print "+" behind the last number

I have no idea how to phrase the title so feel free to make changes! I am stuck on this program that I have made involving a loop. I want the input to be 1 5 which means the code starts adding from 1 and all the way until 5, the expected output would be 1 + 2 + 3 + 4 + 5 = 15 but my code (see below) would print something like 1 + 2 + 3 + 4 + 5 + = 15. How do I get rid of that unwanted addition symbol?

public static void main(String[] args) {

    Scanner keyboard = new Scanner(System.in);
    
    int start = keyboard.nextInt();
    int end = keyboard.nextInt();

    double dend = (double)end;
    double dstart = (double)start;

    double n = (dend - dstart + 1);
        
    double sum = (n/2)*(dend+dstart);

    int intsum = (int)sum; 


    for (int i =start; i <= end; i++) {
        System.out.print(i+" + ");

    }
    
    System.out.print(" = "+intsum);

}

Upvotes: 0

Views: 47

Answers (4)

Baromachine
Baromachine

Reputation: 21

An alternate solution would be to count the number of iterations and check if it is on it's last iteration. If not, then print a "+".

Upvotes: 0

Rajeev
Rajeev

Reputation: 303

As already mentioned by Scary Wombat you can reduce the lopping by one but in your code you are doing string concatenation for each element which not good (because of immutability nature of string in java).

So better to use some mutable string object (either StringBuilder/StringBuffer) and also you can have look at Collectors.joining() (which is introduced in Java8) if you would like implement this using streams.

Upvotes: 0

camickr
camickr

Reputation: 324108

The logic could be something like:

for (int i =start; i <= end; i++) 
{
    if (i > start)
        System.out.print(" + ");

    System.out.print(i);
}

The idea is you only print "+" AFTER the first iteration of the loop.

Another option is to use a StringJoiner:

StringJoiner sj = new StringJoiner(" + ");

for (int i =start; i <= end; i++) 
{ 
    sj.add( i + "" ); // converts the "i" to a string
}

System.out.print( sj.toString() );

The StringJoiner will add the delimiter for you automatically as required.

Upvotes: 0

Scary Wombat
Scary Wombat

Reputation: 44824

You could reduce the looping by one, and then print again

for (int i =start; i < end; i++) {
    System.out.print(i+" + ");

}

System.out.print(end);
System.out.print(" = "+intsum);

or you could have if logic in your loop

for (int i =start; i <= end; i++) {
    System.out.print(i);
    if (i != end) System.out.print(" + ");

}

Upvotes: 1

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