Dfs.c

#include<stdio.h>
int a[20][20],reach[20],n;
void dfs(int v)
{
    int i;
    reach[v]=1;
    for(i=1; i<=n; i++)
        if(a[v][i] && !reach[i])
        {
            printf(" %d->%d",v,i);
            dfs(i);
        }
}
void main()
{
    int i,j,count=0;
    printf(" Enter number of vertices:");
    scanf("%d",&n);
    for(i=1; i<=n; i++)
    {
        reach[i]=0;
        for(j=1; j<=n; j++)
            a[i][j]=0;
    }
    printf(" Enter the adjacency matrix:\n");
    for(i=1; i<=n; i++)
        for(j=1; j<=n; j++)
            scanf("%d",&a[i][j]);
    dfs(1);
    printf("\n");
    for(i=1; i<=n; i++)
    {
        if(reach[i])
            count++;
    }
    if(count==n)
        printf(" Graph is connected\n");
    else
        printf(" Graph is not connected\n");
}