Program Breadth First Search in C

Program

#include <stdio.h>
#include <conio.h>
void BFS(int[20][20], int, int[20], int);
void main()
{
    int n, a[20][20], i, j, visited[20], source;
    printf("****************************************************************");
    printf("\n****************************************************************");
    printf("\n**           Program for Breadth First Search in C            **");
    printf("\n**                   Created by Sheetal Garg                  **");
    printf("\n**                     Assistant Professor                    **");
    printf("\n**                     Phone No:9467863365                    **");
    printf("\n****************************************************************");
    printf("\n****************************************************************");
        printf("\nEnter the number of vertices:");
    scanf("%d", &n);
    printf("\nEnter the adjacency matrix:\n");
    for (i = 1; i <= n; i++)
    {
        for (j = 1; j <= n; j++)
            scanf("%d", &a[i][j]);
    }
    for (i = 1; i <= n; i++)
        visited[i] = 0;
    printf("\nEnter the source node:");
    scanf("%d", &source);
    visited = 1;
    BFS(a, source, visited, n);
    for (i = 1; i <= n; i++)
    {
        if (visited[i] != 0)
            printf("\n Node %d is reachable", i);
        else
            printf("\n Node %d is not reachable", i);
    }
    getch();
}
void BFS(int a[20][20], int source, int visited[20], int n)
{
    int queue[20], f, r, u, v;
    f = 0;
    r = -1;
    queue[++r] = source;
    while (f <= r)
    {
        u = queue[f++];
        for (v = 1; v <= n; v++)
        {
            if (a[u][v] == 1 && visited[v] == 0)
            {
                queue[++r] = v;
                visited[v] = 1;
            }
        } // for v
    }     // while
}

Output 1

****************************************************************
****************************************************************
**           Program for Breadth First Search in C            **
**                   Created by Sheetal Garg                  **
**                     Assistant Professor                    **
**                     Phone No:9467863365                    **
****************************************************************
****************************************************************
Enter the number of vertices:4

Enter the adjacency matrix:
0 1 0 0
1 0 1 1
0 0 0 0
1 1 0 0

Enter the source node:2

 Node 1 is reachable
 Node 2 is reachable
 Node 3 is reachable
 Node 4 is reachable