C++ Program to Check if any Graph is Possible to be Constructed for a Given Degree Sequence

C++Server Side ProgrammingProgramming

It is a program to check possibility of construction of a graph in a given degree sequence.

Input

It takes the no of edges and vertexes.

Output

It shows the random values of a created graph.

Algorithms

Begin
   Declare a function RandomGraphs().
      Declare NoEdge and NoVertex of the integer datatype and pass them as parameter.
      Declare i, j, e[NoEdge][2], c of the integer datatype.
      Initialize i = 0.
      while (i < NoEdge) do
         e[i][0] = rand()%NoVertex+1.
         e[i][1] = rand()%NoVertex+1.
         if(e[i][0] == e[i][1]) then
            continue.
         else
            for(j = 0; j < i; j++)
            if((e[i][0] == e[j][0] && e[i][1] == e[j][1]) || (e[i][0] == e[j][1] && e[i][1] == e[j][0])) then
               i--.
               i++.
            Print “The randomly generated graph:”.
      for(i = 0 to NoVertex-1)
      c = 0;
      Print "Vertex number ".
      Print the number of vertex.
      for(j = 0 to NoEdge-1)
         if(e[j][0] == i+1) then
            Print the value of e[j][1].
            c++.
         else if(e[j][1] == i+1) then
            Print the value of e[j][0].
            c++.
         else if(j == NoEdge-1 and c == 0) then
            Print "This vertex is isolated!!!".
End
Begin
   Declare edg, ver of the integer datatype.
   Print "generation of a random graph: ".
   Print "Enter the number of vertexes for the graph: ".
   Take input of the value of ver variable.
   Print "Enter the number of edges for the graph: ".
   Take input of the value of edg variable.
   Call RandomGraphs(edg, ver) to generate a random undirected graph with edg edges and ver vertexes.
End.

Example

#include<iostream>
#include<stdlib.h>
using namespace std;
void RandomGraphs(int NoEdge, int NoVertex) { // generate random graph.
   int i, j, e[NoEdge][2], c;
   i = 0;
   while(i < NoEdge) { // Build a connection between two vertexes
      e[i][0] = rand()%NoVertex+1;
      e[i][1] = rand()%NoVertex+1;
      if(e[i][0] == e[i][1])
         continue;
      else {
         for(j = 0; j < i; j++) {
            if((e[i][0] == e[j][0] && e[i][1] == e[j][1]) || (e[i][0] == e[j][1] && e[i][1] == e[j][0]))
            i--;
         }
      }
      i++;
   }
   cout<<"The randomly generated graph: \n";
   for(i = 0; i < NoVertex; i++) { // printing the graph
      c = 0;
      cout<<"Vertex number "<<i+1<<": \t { ";
      for(j = 0; j < NoEdge; j++) {
         if(e[j][0] == i+1) {
            cout<<e[j][1]<<" ";
            c++;
         } else if(e[j][1] == i+1) {
            cout<<e[j][0]<<" ";
            c++;
         } else if(j == NoEdge-1 && c == 0)
            cout<<"This vertex is isolated!!!";
      }
      cout<<" }\n";
   }
}
int main() {
   int edg, ver;
   cout<<"generation of a random graph: ";
   // Take the input of the vertex and edges.
   cout<<"\nEnter the number of vertexes for the graph: ";
   cin>>ver;
   cout<<"\nEnter the number of edges for the graph: ";
   cin>>edg;
   RandomGraphs(edg, ver); // Call function to generate a random undirected graph with edg edges and ver vertexes.
}

Output

generation of a random graph:
Enter the number of vertexes for the graph: 5

Enter the number of edges for the graph: 5
The randomly generated graph:
Vertex number 1: { 5 3 }
Vertex number 2: { 3 5 }
Vertex number 3: { 2 5 1 }
Vertex number 4: { This vertex is isolated!!! }
Vertex number 5: { 1 3 2 }
raja
Published on 03-May-2019 12:23:14
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