Check if a Number is Perfect Square or Not Using Java

// Without using Inbuilt Methods of Java

class PerfectSquare{
    public static void main(String args[]){
        int a=Integer.parseInt(args[0]);
	double temp = a;
	int count[] = new int[4];
	count[0]=count[1]=count[2]=count[3]=0;
	while (temp>1){
		if(temp%2==0)
		{	count[0]++; temp /=2; }
		if(temp%3==0)
		{	count[1]++; temp /=3; }
		if(temp%5==0)
		{	count[2]++; temp /=5; }
		if(temp%7==0)
		{	count[3]++; temp /=7; }
		

	}
	
	int y = 1;
	if(count[0]>0 && count[0]%2!=0) y=0;
	if(count[1]>0 && count[1]%2!=0) y=0;
	if(count[2]>0 && count[2]%2!=0) y=0;
	if(count[3]>0 && count[3]%2!=0) y=0;
	
	if(y==1)
		System.out.println("yes it is square");
	else
		System.out.println("no it is not square");		
    }
}

We can use Math class sqrt

// using built in functions
import java.math.*;
class PerfectSquare{
    public static void main(String args[]){
        int a=Integer.parseInt(args[0]);
	int sqrt = (int) Math.sqrt(a);

	if(sqrt*sqrt == a)
		System.out.println("yes it is perfect square");
	else
		System.out.println("no it is not perfect square");
    }
}

Discussion

Give Input as command line arguments : java PerfectSquare 36