heap data structure implimentation

import java.util.Scanner;

public class heap {
    public static class minheap{
        int []a;
        int size;
        int cap;
        minheap(int c){
            a=new int[c];
            size=0;
            cap=c;
        }
        int l(int i){
            return (2*i+1);
        }
        int r(int i){
            return (2*i+2);
        }
        int parent(int i){
            return (i-1)/2;
        }

        public void insert(int x){
            if(size==cap){
                return;
            }
            size++;
            a[size-1]=x;
            int i=size-1;
            while (i!=0 && a[parent(i)]>a[i]) {
                swap(a[i],a[parent(i)]);
                i=parent(i);
            }


        }
        public void minheapfy(int i){
            int ll=l(i);
            int rr=r(i);
            int smallest=i;
            if(ll<size && a[ll]<a[i]){
                smallest=ll;
            }
            if(rr<size && a[rr]<a[smallest]){
                smallest=rr;
            }
            if(smallest !=i){
             swap(a[i],a[smallest]);
             minheapfy(smallest);
            }
        }

        public int extractmin(){
            if(size==0){
                return Integer.MAX_VALUE;
            }
            if(size==1){
                size--;
                return a[0];
            }
            swap(a[0],a[size-1]);
            size--;
            minheapfy(0);
            return a[size];
        }

        public void deckey(int i, int x){
            a[i]=x;
            while(i!=0 && a[parent(i)]>a[i]){
                swap(a[i],a[parent(i)]);
                i=parent(i);
            }
        }

        public void heapbuilder(){
            for(int i=(size-2)/2; i>=0;i--){
                minheapfy(i);
            }
        }

        public void swap(int n, int m){
            int temp= n;
            n=m;
            m=temp;
        }

        public void main(String[] args) {
            Scanner a = new Scanner(System.in);
            int c=a.nextInt();
            minheap z=new minheap(c);
            int length = a.nextInt();
            int [] a1 = new int[length];
            for(int i=0; i<length; i++ ) {
                a1[i]=a.nextInt();
            }
            int i=0;
            while (i<length) {
                z.insert(a1[i]);
                i++;
            }
        }

    }

}