DFS using stacks error!

[Rishav Paul]

#include<iostream>
using namespace std;

class dfs
{
         
             int v,i,k,matrix[20][20],j,color[20],stack[20],top;
             
             public:
             dfs();
             void graph();
             void traversal(int);
};

dfs::dfs()
{         top=-1;k=1;
         for(int i=1 ;i<=20;i++)
         color[i]=0;
}

void dfs::graph()
{
     int e,s;
    cout<<"Enter the number of vertices\n";
    cin>>v;
    cout<<"Enter the number of edges\n";
    cin>>e;
    
    cout<<"Enter the edges\n";
    
    for(int k=1;k<=e;k++)
    {
     cin>>i>>j;
     matrix[i][j]=1;
     matrix[j][i]=1;
    }
    
    cout<<"Enter the source vertex\n";
    cin>>s;
    
    traversal(s);
}  
void dfs::traversal(int s)
{   
    cout<<s<<" ";
    color[s]=1;
    
    while(k<v)
    {
              for(j=1;j<=v;j++)
              {
                               if((matrix[s][j]==1)&&(color[j]==0))
                               {
                                
                                stack[++top]=j;
                                color[j]=1;
                               }
              }
              
              s=stack[--top];
              cout<<s<<" ";
              k++;
    }
}


int main()
{
    dfs a;
    a.graph();
    system("pause");
    return 0;
}

Enter the number of vertices
3
Enter the number of edges
2
Enter the edges
1 3
1 2
Enter the source vertex
1
1 2 0 Press any key to continue . . . 

I can see no reason why the 3rd vertex is not getting visited. Please help guys..