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Category：Languages

I'm trying to write a program that computes the sum of the first n positive odd integers.

I'm having trouble figuring out how to incorporate n into finding the sum. I already have a do/while loop to ensure I get a positive value when assigning n value. I know that I have to use a for loop but I'm not really sure how I would do that.

`Scanner input = new Scanner(System.in); // open input stream String cleanUpStr; // clean kbd buffer int n; // number int sum; // sum of numbers int cntr; // counter for loop cleanUpStr = "nothing yet"; n = 0; sum = 0; cntr = 0; //prompt user for the value of n // use a loop to ensure a positive output do { System.out.println("Enter the value of n"); n = input.nextInt(); cleanUpStr = input.nextLine(); // print error if n is invalid if (n < 0) { System.out.println("Invalid n value of " + n + ", try again."); } // end if }while(n < 0); for(cntr = 0; cntr < n; ++cntr) { } // end for } // end main `

For example: if n = 5, then this should compute 1 + 3 + 5 + 7 + 9.

`Stream`

is good, but if you're a beginner a plain old `for`

loop is your best friend.

`public static int sumForOddNumbers(int total) { int sum = 0; for(int i = 0, odd = 1; i < total; i++, odd += 2) { sum += odd; } return sum; } `