#include<stdio.h>

main()

{

    int n1,n2;

        n1=1;

        n2=5;

        printf("       ");

        while(n1<=4&&n2>=1)

        {

            printf("%d,%d,",n1,n2);

            n1++;

            n2--;

        }

            printf("%d,%d",n1,n2);

}

#include<stdio.h>

main()

{

    int n1,n2;

        n1=1;

        n2=5;

        printf("       ");

        do

        {

            printf("%d,%d,",n1,n2);

            n1++;

            n2--;

        }

        while(n1<=4&&n2>=1);

            printf("%d,%d",n1,n2);

}

#include<stdio.h>

main()

{

    int n1,n2;

        printf("       ");

            for(n1=1,n2=5;  n1<=4,n2>1;  n1++,n2--)

                    {

                        printf("%d,%d,",n1,n2);

                    }

                    printf("%d,%d",n1,n2);

}