C++ Programming Code Examples
C++ > Computer Graphics Code Examples
C++ Program to Find all Back Edges in a Graph
/* C++ Program to Find all Back Edges in a Graph
This C++ program, using recursion, to display the number of back edges in a graph. A back edge is one in which a node points to one of it's ancestors. */
#include<iostream>
#include<conio.h>
using namespace std;
struct node_info
{
int no;
}*q = NULL,*r = NULL;
struct node
{
node_info *pt;
node *next;
}*top = NULL,*p = NULL,*np = NULL;
void push(node_info *ptr)
{
np = new node;
np->pt = ptr;
np->next = NULL;
if (top == NULL)
{
top = np;
}
else
{
np->next = top;
top = np;
}
}
node_info *pop()
{
if (top == NULL)
{
cout<<"underflow\n";
}
else
{
p = top;
top = top->next;
return(p->pt);
delete(p);
}
}
void back_edges(int *v,int am[][7],int i,int k)
{
cout<<"\n\ndisplaying back edges\n\n";
q = new node_info;
q->no = i;
push(q);
v[i] = 1;
for (int j = 0; j < 7; j++)
{
if (am[i][j] == 1 && v[j] == 0)
{
c++;
back_edges(v,am,j,i);
}
else if (am[i][j] == 0)
continue;
else if ((j == k) && (am[i][k] == 1 && v[j] == 1))
continue;
else
{
cout<<"Back edge present between "<<i<<" th node and "<<j<<" th node"<<endl;
am[i][j] = 0;
am[j][i] = 0;
continue;
}
}
r = pop();
return;
}
int main()
{
int v[7],am[7][7];
for (int i = 0; i < 7; i++)
v[i] = 0;
for (int i = 0; i < 7; i++)
{
cout<<"enter the values for adjacency matrix row:"<<i + 1<<endl;
for(int j = 0; j < 7; j++)
{
cin>>am[i][j];
}
}
back_edges(v,am,0,0);
getch();
}
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