C++ code to generate minimum spanning tree using Prim’s algorithm.

Description :
It works as follows:

1. Create a tree containing a single vertex that is  chosen arbitrarily from the graph.
2. Create a set containing all the edges in the graph.Loop until every edge in the set connects two vertices in the tree.
3. Remove from the set an edge with minimum weight that connects a vertex in the tree with a vertex not in the tree.
4.  Add that edge to the tree.

Code :
#include<stdio.h>
#include<conio.h>
#include<iostream.h>
#include<process.h>
#include<stdlib.h>
class prims
{
private:
int a[10][10],spantree[10][10],n;
int visit[20],from[20],dist[20];
public:
void dir();
void span();
}c;
void prims::dir()
{
int v1,v2,i,j,w;
char ch;
cout<<”\n\nEnter Number of nodes: “;
cin>>n;
do
{
cout<<”\n\nEnter the Source vertex: “;
cin>>v1;
cout<<”\nEnter The Destination Vertex: ” ;
cin>>v2;
cout<<”\nEnter The Weight Of Edge: “;
cin>>w;
a[v1][v2]=w;
a[v2][v1]=w;
cout<<”\n\nDo You Want To Continue?(Y/N): ” ;
flushall();
cin>>ch;
}while(ch==’y'||ch==’Y');
getch();
}
void prims::span()
{
int u,v,y,i,ne,mindist,j,mincost;
ne=0;
mincost=0;
cout<<”\nEnter Your Starting vertex: “;
cin>>v;
visit[v]=1;
for(i=0;i<n;i++)
{
for(j=0;j<n;j++)
{
if(a[i][j]==0)
a[i][j]=9999;
}
}
for(i=0;i<n;i++)
{
dist[i]=a[0][i];
}
while(ne<=n-1)
{
mindist=9999;
for(i=0;i<n;i++)
{
if((visit[i]==0)&&(dist[i]<mindist))
{
v=i;
mindist=dist[i];
}
}
u=from[v];
spantree[u][v]=dist[v];
spantree[v][u]=dist[v];
visit[v]=1;
ne++;
for(i=1;i<n;i++)
{
if((visit [i]==0)&&(a[i][v]<dist[i]))
{
dist[i]=a[i][v];
from[i]=v;
}
}
mincost+=mindist;
}
mincost=mincost-9999;
cout<<”\nMinimum Spanning Tree is:\n”;
for(i=0;i<n;i++)
{
cout<<”\n”;
for(j=0;j<n;j++)
{
cout<<”\t”<<spantree[i][j];
}
}
cout<<”\n\nMinimum cost of Spanning tree is: ” <<mincost;
getch();
}
void main()
{
int ch;
char f;
clrscr();
cout<<”\n\n\t\t\t\t\t\t\t\t\t\t\t…. Minimum Cost Spanning Tree Using Prim’s Algorithm ….”;
do
{
cout<<”\n\n MENU: “;
cout<<”\n\n\t1.Create Graph\n\n\t2.Find Minimum Cost Spanning Tree\n\n\t3.Exit”;
cout<<”\n\nEnter Your Choice: ” ;
cin>>ch;
switch(ch)
{
case 1:
c.dir();
getch();
break;
case 2:
c.span();
break;
case 3:
exit(0);
break;
default:
cout<<”\n\nPlease Enter Valid choice.”;
break;
}
flushall();
cout<<”\n\nDo You Want To Continue To main Program?(Y/N): ” ;
cin>>f;
}while(f==’Y’ || f==’y');
getch(); }