欧拉12，三角形数字的列出因子

Question

I have been working on this Euler problem (12) and I'm stuck. I want each triangle number to be only shown once with all it's factors but I don't know how.

public class Euler12 {
    public static void main(String[] args) {  
        int count1 = 0;
        int trinumber = 0;

        while (count1 < 10) {   
            count1++;
            trinumber += count1;  
            for (int count2 = 1; count2 <= trinumber; count2++) {
                if(trinumber % count2 == 0) {   
                    System.out.println("trinumber: " + trinumber + " " + "factors: " + count2);
                }
            }
        }
    }      
}

Answer 1

Change your while loop to this

while (count1 < 10) {
    count1++;
    trinumber += count1;
    System.out.print("trinumber: " + trinumber + ", factors: ");
    for (int count2 = 1; count2 <= trinumber; count2++)
        if (trinumber % count2 == 0)
            System.out.print(count2 + ", ");
    System.out.println();
}

so that this

    System.out.print("trinumber: " + trinumber + ", factors: ");

is only executed 10 times, while this

    System.out.print(count2 + ", ");

prints all the factors for the same number always in the same line