寻找和为定值的两个数

#include<iostream>using namespace std;bool find_num(int data[] , int length , int sum , int &first_num , int &second_num){    if(length < 1)        return true;    int begin = 0;    int end = length - 1;    while(begin < end)    {        int current_sum = data[begin] + data[end];        if(current_sum == sum)        {            first_num = data[begin];            second_num = data[end];            return true;        }        else if(current_sum > sum)            end--;        else             begin++;    }    return false;}int main(){    int data[] = {1 ,3 , 4 , 7 , 12 , 15};    int length = sizeof(data)/sizeof(int);    int first_num = 0 ;    int second_num = 0;    int sum = 11;    if(find_num(data , length , sum , first_num , second_num))    {        cout<<first_num<<" "<<second_num<<endl;    }    else        cout<<"不存在"<<endl;    return 0;}