Topological Sorting in Java

import java.util.Scanner;


public class Topological {
int vertices,edges;
int graph[][],indegree[],visited[];



public Topological() {
Scanner sc=new Scanner(System.in);
System.out.println("Enter total no of vertices : ");
vertices=sc.nextInt();
graph=new int [vertices][vertices];
indegree=new int [vertices];
visited=new int [vertices];

for(int i=0;i<vertices;i++){ //Initialization of graph
for(int j=0;j<vertices;j++){
graph[i][j]=0;
}
indegree[i]=0;
visited[i]=0;
}
}

void create(){
System.out.println("Enter total no of Edges : ");
Scanner sc=new Scanner(System.in);
edges=sc.nextInt();

System.out.println("Enter source and destination vertex ");

for(int i=0;i<edges;i++){
System.out.println(++i+".");
--i;
System.out.println("Source vertex : ");
int u=sc.nextInt();
System.out.println("Destination vertex : ");
int v=sc.nextInt();
graph[u][v]=1;
}
}


int cal_indegree(int ver){
int count=0;
for(int i=0;i<vertices;i++){
if(graph[i][ver]==1)
count++;
}
return count;
}

void topological_sorting(){
int j;
for(int i=0;i<vertices;i++){
indegree[i]=cal_indegree(i);
}

System.out.println("Result of Topological sorting is : ");
for(int i=0;i<vertices;i++){
j=0;
while(j<vertices){
if(visited[j]==0 && indegree[j]==0){
visited[j]=1;
System.out.print(j+" ");
for(int k=0;k<vertices;k++){
if(graph[j][k]!=0)
indegree[k]--;
}
break;
}
j++;
}
if(j==vertices){
System.out.println("Graph has a cycle");
break;
}

}
}


public static void main(String[] args) {
Topological topo=new Topological();
topo.create();
topo.topological_sorting();

}

}