DNA （C语言代码）

#include "stdafx.h"

int main()

{

     int i,j,k,l,n, a[15], b[15];

     scanf("%d", &n);

     for (i = 0; i < n; i++)

     {

          scanf("%d %d", &a[i],&b[i]);

     }

     for (i = 0; i < n; i++)            //控制要显示的DNA数量

     {

         for (l = 0; l < b[i]; l++)     //控制DNA重复

             {

             if (l == 0) //如果是第一个

             {

                 for (j = 0; j < a[i]; j++)

                 {

                     for (k = 0; k < a[i]; k++)

                         {

                              if ((j == k) || (j + k == a[i] - 1))

                             {

                                 printf("X");

                             }

                             else

                                 printf(" ");

                         }

                     printf("\n");

                 }

               }

             else                         //如果是后续重复的，则从第二行开始            

             {

                 for (j = 1; j < a[i]; j++)

                 {

                     for (k = 0; k < a[i]; k++)

                     {

                         if ((j == k) || (j + k == a[i] - 1))

                             {

                             printf("X");

                             }

                         else

                             printf(" ");

                     }

                     printf("\n");

                     }

                 }

             }

         printf("\n");

     }

        return 0;

}