how to convert this java code to c++

public class QuickFindUF {

private int[] id;

private int count;

public QuickFindUF(int n) {

count = n;

id = new int[n];

for (int i = 0; i

id[i] = i;

}

public int count() {

return count;

}

public int find(int p) {

validate(p);

return id[p];

}

private void validate(int p) {

int n = id.length;

if (p = n) {

throw new IllegalArgumentException("index " + p + " is not between 0 and " + (n-1));

}

}

public boolean connected(int p, int q) {

validate(p);

validate(q);

return id[p] == id[q];

}

public void union(int p, int q) {

validate(p);

validate(q);

int pID = id[p];

int qID = id[q];

if (pID == qID) return;

for (int i = 0; i

if (id[i] == pID) id[i] = qID;

count--;

}

public static void main(String[] args) {

int n = StdIn.readInt();

QuickFindUF uf = new QuickFindUF(n);

while (!StdIn.isEmpty()) {

int p = StdIn.readInt();

int q = StdIn.readInt();

if (uf.find(p) == uf.find(q)) continue;

uf.union(p, q);

StdOut.println(p + " " + q);

}

StdOut.println(uf.count() + " components");

}

}

public static void main(String[] args) { int n = stdin.readInt(); QuickFindUF uf = new QuickFindUF(n); while (!StdIn.isEmpty()) { int p = stdin.read Int(); int q = Stdin.readInt(); if (uf.find(p) == uf.find(q)) continue; uf.union (p, q); Stdout.println(p + " " + q); Stdout.println(uf.count() + " components")