Sum of Numbers (expected output issue)

Question

I am having issues with my program. The point is that the user needs to enter a starting number (ex:1) and an ending number (ex:5), the output should be 1+2+3+4+5=15. I, on the other hand, am getting 1+2+3+4+5+. I am unsure as to how to fix it, any help would be greatly appreciated. Thanks!Also is there anyway to not return null? My program keeps asking me to return it to null.

import java.util.Scanner;

public class SumOfNumbers  
    {
    public String getSum(int start, int end) 

        { 
        int sum=0;

           Scanner scanner = new Scanner(System.in) ; //Scanner used to get keyboard values 

           System.out.println("Enter your starting number: "); 
           start = scanner.nextInt(); //first number 

           System.out.println("Enter your ending number: "); 
           end =scanner.nextInt(); //second number 

           for(int i=start;i<=end;i++) 
           { 
               sum=sum+i; //calculating sum 
               scanner.close();
               System.out.print(i + "+");

           }
        return null;

        }
    }

Answer 1

Here is a method that will do what you are asking for:

public String output(int startNum, int endNum) {
    String reply = "";
    int answer = 0;
    for (int x = startNum; x <= endNum; x++) {
        if (x == startNum) reply = "" + x;
        else if (x == endNum) reply = reply + "+" + x + "=";
        else reply = reply + "+" + x;
        answer += x;
    }
    reply = reply + answer;
    return reply;
}

---

Here is the output:

System.out.println(output(1,10));

1+2+3+4+5+6+7+8+9+10=55

Answer 2

You currently output + after every number, instead output the first number and then start looping (but in the loop, output a + before every number). Also, don't forget to output the sum after your loop. Something like

int sum = start;
System.out.print(start);
for (int i = start + 1; i <= end; i++) {
    System.out.print("+" + i);
    sum += i;
}
System.out.println(" = " + sum);

However, since you apparently need to return this result as a String you should be doing something like

int sum = start;
StringBuilder sb = new StringBuilder();
sb.append(start);
for (int i = start + 1; i <= end; i++) {
    sb.append("+").append(i);
    sum += i;
}
sb.append("=").append(sum);
// System.out.println(sb.toString());
return sb.toString();

And you should probably be using the start and end values you pass to the function (instead of ignoring them and prompting the user in the function).

I have tried to add both of the outputs together in the return statement by making them into strings but no luck

The code above is logically equivalent to (but more efficient then)

int sum = start;
String result = String.valueOf(start);
for (int i = start + 1; i <= end; i++) {
    result = result + "+" + i;
    sum = sum + i;
}
result = result + "=" + sum;
// System.out.println(result);
return result;

It could also be written more concisely like

int sum = start;
String result = String.valueOf(start);
for (int i = start + 1; i <= end; i++) {
    result += "+" + i;
    sum += i;
}
result += "=" + sum;
// System.out.println(result);
return result;

Or, if we're using Java 8+, with lambdas like

StringBuilder sb = new StringBuilder(String.valueOf(start));
int sum = IntStream.rangeClosed(start, end).sum();
IntStream.rangeClosed(start + 1, end).forEach(x -> sb.append("+").append(x));
sb.append("=").append(sum);
// System.out.println(sb);
return sb.toString();

Answer 3

hope this will help

class SumOfNumbers  
    {
    public void getSum(int start, int end) 

        { 
        int sum=0;

           Scanner scanner = new Scanner(System.in) ; //Scanner used to get keyboard values 

           System.out.println("Enter your starting number: "); 
           start = scanner.nextInt(); //first number 

           System.out.println("Enter your ending number: "); 
           end =scanner.nextInt(); //second number 

           for(int i=start;i<=end;i++) 
           { 
               sum=sum+i; //calculating sum 
               scanner.close();
               if (i==end) {
                   System.out.print(i );
               }
               else {
                   System.out.print(i + "+");
               }


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

        }
    }

output

Enter your starting number: 
1
Enter your ending number: 
15
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15=120