C++ Programming Code Examples
C++ > Computer Graphics Code Examples
Program to Create a Random Graph Using Random Edge Generation
/* Program to Create a Random Graph Using Random Edge Generation
- This algorithm generates a undirected random graph for some random number of edges and vertexes.
- The time complexity of this algorithm is O(v*e).
- This algorithm randomly assigns a number of vertexes and edges of the graph.
- It connects vertexes randomly and generates cyclic, acyclic or disconnected undirected graphs. */
#include<iostream>
#include<stdlib.h>
using namespace std;
// A function to generate random graph.
void GenerateRandGraphs(int NOE, int NOV)
{
int i, j, edge[NOE][2], count;
i = 0;
// Build a connection between two random vertex.
while(i < NOE)
{
edge[i][0] = rand()%NOV+1;
edge[i][1] = rand()%NOV+1;
if(edge[i][0] == edge[i][1])
continue;
else
{
for(j = 0; j < i; j++)
{
if((edge[i][0] == edge[j][0] && edge[i][1] == edge[j][1]) || (edge[i][0] == edge[j][1] && edge[i][1] == edge[j][0]))
i--;
}
}
i++;
}
// Print the random graph.
cout<<"\nThe generated random random graph is: ";
for(i = 0; i < NOV; i++)
{
count = 0;
cout<<"\n\t"<<i+1<<"-> { ";
for(j = 0; j < NOE; j++)
{
if(edge[j][0] == i+1)
{
cout<<edge[j][1]<<" ";
count++;
}
else if(edge[j][1] == i+1)
{
cout<<edge[j][0]<<" ";
count++;
}
else if(j == NOE-1 && count == 0)
cout<<"Isolated Vertex!";
}
cout<<" }";
}
}
int main()
{
int n, i, e, v;
cout<<"Random graph generation: ";
// Randomly assign vertex and edges of the graph.
v = 11+rand()%10;
cout<<"\nThe graph has "<<v<<" vertexes.";
e = rand()%((v*(v-1))/2);
cout<<"\nThe graph has "<<e<<" edges.";
// A function to generate a random undirected graph with e edges and v vertexes.
GenerateRandGraphs(e, v);
}
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