I am trying to run this program but it gives error initwindow() not initialized

Question

The code basically implements B-MFR Routing protocol. It is probably a trivial error but I can't resolve it.

#include <graphics.h>
        #include<conio.h>
        #include<stdio.h>
        #include<stdlib.h>
        #include<math.h>
        #include<string.h>
        #include<time.h>
        #define RADI 125
        
        int points[100][2];
        int dist[25][25];
        int k;
        int path[25];
        
        int distance(int x1,int y1,int x2,int y2)
        {
              return (int)sqrt(pow(x1-x2,2)+pow(y1-y2,2));
        }
        
        
        void printscreen()
        {
             char str[5];
             //cleardevice();
             for(int i=0; i<25; i++)
            {
                     circle(points[i][0],points[i][1],3);
                     itoa(i+1,str,10);
                     outtextxy(points[i][0]+3,points[i][1]+3,str);
            }
        }
        void drawgraphics(int x1,int y1,int x2,int y2, int rad)
        {
             int x=RADI;
             while(x!=rad)
             {
                          //printscreen();
                          setcolor(15);
                          circle(x1,y1,x);
                          printscreen();
                          delay(15);
                          setcolor(0);
                          setfillstyle(EMPTY_FILL ,0);
                          circle(x1,y1,x);
                          x--;
             }
                   setcolor(15);
                   printscreen();
                   line(x1,y1,x2,y2);
                   //circle(x1,y1,rad);
                   delay(100);
        }
        void getpath(int start,int end,int rad)
        {
             int flag,current=start,min,prev;
             path[0]=start+1;
             k=1;
             while (current!=end)
             {
                   rad=RADI;
                   flag=1;
                   prev=current;
                   while (flag)
                   {
                         min=1000;
                         for (int i=0;i<25;i++)
                         {
                             if (rad==dist[current][i]&&dist[current][end]>dist[i][end])
                             {
                                flag=0;
        
                                if (min>dist[i][end])
                                {
                                   min=dist[i][end];
                                   current=i;
                                }
                             }
                         }
                         rad--;
                         if(rad<0)
                         {
                                  printf("\nNo Node found in Radius.\n");
                                  return;
                         }
                   }
                   path[k]=current+1;
                   drawgraphics(points[prev][0],points[prev][1],points[current][0],points[current][1],rad+1);
                   k++;
             }
        }
        int main()
        {
            initwindow(640,480,"B-MFR Routing Protocol");
            srand (time(NULL));
        
            for(int i=0; i<25; i++)
            {
                     points[i][0]= rand() % 550 + 50;
                     points[i][1]= rand() % 400 + 50;
            }
            printscreen();
        
            for(int i=0; i<25; i++)
            {
                    for(int j=0; j<25; j++)
                    {
                            dist[i][j]=distance(points[i][0],points[i][1],points[j][0],points[j][1]);
                    }
            }
        
            int start,end;
            printf("Enter start:");
            scanf("%d",&start);
            printf("Enter end:");
            scanf("%d",&end);
            start--;
            end--;
        
            getpath(start,end,RADI);
            printf("\n");
            printf("%d ",path[0]);
            for(int i=1;i<k;i++)
            {
                    printf("%d ",path[i]);
                    line(points[path[i-1]-1][0],points[path[i-1]-1][1],points[path[i]-1][0],points[path[i]-1][1]);
            }
            getche();
        }

Answer 1

The Dark Certainly appears to be on the right track. None of the openbgi header files mention initwindow. There is an initgraph

void initgraph(int   *graphdriver, int   *graphmode, const char  *pathtodriver);

I did find a fairly ancient reference to BGI which has a graphics.h that contains the initwindow declaration that appears to be missing.

Without knowing precisely which collection of 3rd party code the OP is using it is hard to say what's really going on here.