BFS

#include<stdio.h>
void bfs(int v);

int a[20][20],q[20],visited[20],n,i,j,f=0,r=-1;

int main() {
    int v;
    //Enter the number of vertices
    scanf("%d",&n);
    //initialization loop
    for (i=1;i<=n;i++) {
        q[i]=0;
        visited[i]=0;
    }
    //Enter graph data in matrix form
    for (i=1;i<=n;i++)
      for (j=1;j<=n;j++)
       scanf("%d",&a[i][j]);
    //Enter the starting vertex
    scanf("%d",&v);
    q[++r]=v;
    bfs(v);

    return 0;
}

void bfs(int v) {
    for (i=1;i<=n;i++)
      if(a[v][i] && !visited[i]){
       q[++r]=i;
      }
    if(f<=r) {
        if(visited[q[f]]==0)
            printf("%d\t",q[f]);
        visited[q[f]]=1;
        bfs(q[f++]);
    }
}