searching for a given number in adjacent array

adjacent_numbers.cpp

#include <iostream>
#include <vector>

using namespace std;

bool search_adj(const vector<int> &arr, int s) {
	bool ret = false;
	size_t i;
	for( i = 0; i < arr.size(); ) {
		if( arr[i] == s ) {
			ret = true;
			break;
		}
		else {
			i += abs(s-arr[i]);
		}
	}
	return ret;
}

int main() {
	int n;
	cin >> n;
	int i;
	vector<int> arr(n);
	for( i = 0; i < n; i++ )
		cin >> arr[i];
	int s;//number to search
	cin >> s;
	if( search_adj(arr, s) )
		cout << "Found" << endl;
	else
		cout << "Not found" << endl;
	return 0;
}