Rail-Fence cipher encryption-decryption

#include<stdio.h>

#include<conio.h>

#include<string.h>

#include<ctype.h>

void main()

{

            int i,j=0,d,k=0;

            char p[50],ct[50][50];

            clrscr();

            printf("Enter the plain text:\n");

            gets(p);

            printf("\nEnter the depth in the integer:");

            scanf("%d",&d);

            //declare null for empty array values

            for(i=0;i<50;i++)

            {

                        for(j=0;j<50;j++)

                        {

                                    ct[i][j]='\0';

                        }

            }

            k=0;

       //loop up to string lenght of the pliantext

            {

            for(i=0;i<strlen(p);i++)

            {

                        for(j=0;j<d;j++)

                        {

                                    if(k<=strlen(p))

                               ct[i][j]=p[k];

                                    k++;

                        }

                        ct[i][j]='\0';

                        }

            }

            for(i=0;i<d;i++)

            {

                        for(j=0;j<strlen(p);j++)

                        {

                                    if(ct[j][i]!='\0')

                                       {

                                           printf("%c",ct[j][i]);

                                       }

                        }

                        printf("\n");

            }

            // Read the text

            printf("\nThe encrypted text is:\n");

            for(i=0;i<d;i++)

            {

                        for(j=0;j<strlen(p);j++)

                        {

                                    if(ct[j][i]!='\0')

                                    printf("%c",ct[j][i]);

                        }

            }

            getch();

}

output: