Floyd–Warshall algorithm

 #include<iostream.h>  
 #include<conio.h>  
 int a[20][20],cost[20][20],p[20][20],i,j,n,k;  
 class path  
 {  
  public:  
    void get();  
    void allpair(int a[20][20],int n);  
    void put();  
 };  
 void path:: get()  
 {  
  cout<<"\n\t\tALL PAIR SHORTEST PATH\n";  
  cout<<"\nEnter the no of vertices : ";  
  cin>>n;  
  cout<<"\nEnter the cost\n";  
  for(i=1;i<=n;i++)  
  {  
    for(j=1;j<=n;j++)  
    {  
      if(i==j)  
      {  
        cost[i][j]=p[i][j]=0;  
        a[i][j]=cost[i][j];  
      }  
      else  
      {  
        cout<<"\ncost["<<i<<"]["<<j<<"]=";  
        cin>>cost[i][j];  
        a[i][j]=cost[i][j];  
      }  
    }  
      cout<<"\n";  
  }  
 }  
 void path:: allpair(int a[20][20],int n)  
 {  
  for(k=1;k<=n;k++)  
  {  
    for(i=1;i<=n;i++)  
    {  
      for(j=1;j<=n;j++)  
      {  
        if((a[i][k]+a[k][j])<a[i][j])  
        {  
         a[i][j]=a[i][k]+a[k][j];  
         p[i][j]=k;  
        }  
      }  
    }  
  }  
 }  
 void path:: put()  
 {  
  cout<<"\n\n\n\n\n\nALL PAIR SHORTEST PATH\n\n\n";  
  for(i=1;i<=n;i++)  
  {  
    for(j=1;j<=n;j++)  
      cout<<'\t'<<a[i][j];  
    cout<<"\n";  
  }  
  cout<<"\n\n\nPath Matrix\n";  
  for(i=1; i<=n; i++)  
  {  
    for(j=1; j<=n; j++)  
      cout<<'\t'<<p[i][j];  
    cout<<"\n";  
  }  
 }  
 void main()  
 {  
  path p;  
  clrscr();  
  p.get();  
  p.allpair(a,n);  
  p.put();  
  getch();  
 }