Program to check whether a graph is connected or not using DFS method

Program:

#include<stdio.h>
void DFS(int[20][20], int, int[20], int);
int main()
{
    int n, a[20][20], i, j, visited[20], source;
    printf("****************************************************************");
    printf("\n****************************************************************");
    printf("\n**             Program for Depth 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);
    DFS(a, source, visited, n);
    for (i = 1; i <= n; i++)
    {
        if (visited[i] == 0)
        {
            printf("\nGraph is not connected");
            break;
        }
    }
    if(i>n)
    printf("\nGraph is connected\n");
    return 0;
  }
void DFS(int a[20][20], int u, int visited[20], int n)
{
    int v;
    visited[u] = 1;
    for (v = 1; v <= n; v++)
    {
        if (a[u][v] == 1 && visited[v] == 0)
            DFS(a, v, visited, n);
    }
}

OUTPUT 1

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

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

Enter the source node: 1

Graph is connected

OUTPUT 2:

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

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

Enter the source node: 2

Graph is not connected