gistfile1.txt

#include <iostream>
#include <fstream>
#include <vector>
#include <utility>
using namespace std;
char grid[4][4];
bool used[4][4] = {0};
void clear(){//set all used array to false
	for (int i = 0; i < 4; i++)
		for (int j = 0; j < 4; j++)
			used[i][j]=false;
}	
bool recur(string str, int x, int y, int p) {
	int direction[] = {1, 0, -1};
	if (str[p] != grid[x][y]) return false;
	else used[x][y] = true;
	if (p == str.length() - 1 && str[p] == grid[x][y]) return true;
	for (int i = 0; i < 3; i++) {
		for (int j = 0; j < 3; j++) {
			int nextX = x + direction[i], nextY = y + direction[j];
			if ((nextX < 4 && nextX >= 0) && (nextY < 4 && nextY >= 0) && !used[nextX][nextY] && recur(str, nextX, nextY, p + 1))
				return true;
		}
	}
	return false;
}
int main() {
	for (int i = 0; i < 4; i++)
		for (int j = 0; j < 4; j++)
			cin >> grid[i][j];	//input grid
	ifstream fin("words.txt");
	string str;
	while (fin >> str) {
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 4; j++) {
				//find first char's position of str
				if (grid[i][j] == str[0]) {
					clear();
					if (recur(str, i, j, 0)){//if recur result is true
						cout << str << endl;
						break;
					}
					
				}
			}
		}
	}
}