求数组中和为某个值的一个组合

#include<iostream>
#include<algorithm>
using namespace std;

//给定一个和，求数组中和为这个值的一组数，O(n)
bool findTwoNumOfSum(int a[],int n,int sum,int &num1,int &num2)
{
	int i=0,j=n-1;
	while(i<j)
	{
		if(a[i]+a[j]>sum)
			j--;
		if(a[i]+a[j]<sum)
			i++;
		if(a[i]+a[j]==sum)
		{
			num1=a[i];
			num2=a[j];
			return true;
		}
	}
	return false;
}
void print(int a[],int n)
{
	for(int i=0;i<n;i++)
		cout<<a[i]<<" ";
	cout<<endl;
}
void main()
{
	int num1,num2;
	int a[]={1,8,2,4,0,2,9};
	int n=sizeof(a)/sizeof(int);
	print(a,n);
	sort(a,a+n);
	print(a,n);
	findTwoNumOfSum(a,n,4,num1,num2);
	cout<<"num1:"<<num1<<"num2:"<<num2<<endl;
	system("pause");
}