Go: package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
	"reflect"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func scanBoard() [][]int {
	ret := make([][]int, 8)
	for k := range ret {
		ret[k] = make([]int, 8)
		for l := range ret[k] {
			ret[k][l] = 0
		}
	}
	for i := 0; i < 8; i++ {
		scanner.Scan()
		row := strings.Split(scanner.Text(), "")
		if reflect.DeepEqual(row, []string{}) {
			break
		}
		for j := 0; j < 8; j++ {
			ret[i][j], _ = strconv.Atoi(row[j])
		}
	}
	return ret
}

var emptyBoard = [][]int{{0,0,0,0,0,0,0,0},
						 {0,0,0,0,0,0,0,0},
						 {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0}}

func main() {
	for {
		var board [][]int
		var ans string
		if board = scanBoard(); reflect.DeepEqual(board, emptyBoard) {
			break
		}
		// fmt.Println(board)
		for i := 0; i < 7; i++ {
			for j := 0; j < 7; j++ {
				if board[i][j] == 1 && board[i+1][j] == 1 && board[i][j+1] == 1 && board[i+1][j+1] == 1 {
					ans = "A"
				}
			}
		}
		for i := 0; i < 5; i++ {
			for j := 0; j < 8; j++ {
				if board[i][j] == 1 && board[i+1][j] == 1 && board[i+2][j] == 1 && board[i+3][j] == 1 {
					ans = "B"
				}
			}
		}
		for i := 0; i < 8; i++ {
			for j := 0; j < 5; j++ {
				if board[i][j] == 1 && board[i][j+1] == 1 && board[i][j+2] == 1 && board[i][j+3] == 1 {
					ans = "C"
				}
			}
		}
		for i := 0; i < 6; i++ {
			for j := 0; j < 7; j++ {
				if board[i][j+1] == 1 && board[i+1][j] == 1 && board[i+1][j+1] == 1 && board[i+2][j] == 1 {
					ans = "D"
				}
			}
		}
		for i := 0; i < 7; i++ {
			for j := 0; j < 6; j++ {
				if board[i][j] == 1 && board[i][j+1] == 1 && board[i+1][j+1] == 1 && board[i+1][j+2] == 1 {
					ans = "E"
				}
			}
		}
		for i := 0; i < 7; i++ {
			for j := 0; j < 6; j++ {
				if board[i][j+1] == 1 && board[i][j+2] == 1 && board[i+1][j] == 1 && board[i+1][j+1] == 1 {
					ans = "G"
				}
			}
		}
		for i := 0; i < 6; i++ {
			for j := 0; j < 7; j++ {
				if board[i][j] == 1 && board[i+1][j] == 1 && board[i+1][j+1] == 1 && board[i+2][j+1] == 1 {
					ans = "F"
				}
			}
		}
		fmt.Println(ans)
	}
}

C++: #include<bits/stdc++.h>
#include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#include<math.h>
#include<bitset>
using namespace std;
int main(){
	int a,b;
	char map[64];
	int movex[4]={1,0,-1,0},movey[4]={0,1,0,-1};
	while(cin>>map[0]){
		for(int i=1;i<64;i++){
			cin>>map[i];
		}
		int i,j;
		for(i=0;i<64;i++){
			if(map[i]=='1'){
				break;
			}
		}
		if(map[i+1]=='1'){
			if(map[i+8]=='1'&&map[i+9]=='1'){
				cout<<"A"<<endl;
			}
			else if(map[i+2]=='1'&&map[i+3]=='1'){
				cout<<"C"<<endl;
			}
			else if(map[i+9]=='1'&&map[i+10]=='1'){
				cout<<"E"<<endl;
			}
			else if(map[i+7]=='1'&&map[i+8]=='1'){
				cout<<"G"<<endl;
			}
		}
		else if(map[i+8]=='1'){
			if(map[i+16]=='1'&&map[i+24]=='1'){
				cout<<"B"<<endl;
			}
			else if(map[i+7]=='1'&&map[i+15]){
				cout<<"D"<<endl;
			}
			else if(map[i+9]=='1'&&map[i+17]=='1'){
				cout<<"F"<<endl;
			}
		}
		memset(map,'0',sizeof(map));
	}
	return 0;
}

C++: #include<iostream>
#include<string>

using namespace std;
string data[8];

int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
struct P{
	P(){};
	P(int a,int b){
		x=a;
		y=b;
	}
	int x,y;
};

bool input(){
	for(int i=0;i<8;i++){
		cin>>data[i];
		if(data[i].empty())return false;
	}
	return true;
}
int main(){
	
	while(input()){
		P o;
		for(int i=0;i<8;i++){
			for(int j=0;j<8;j++){
				if(data[i][j]=='1'){
					o=P(j,i);
					goto suc;
				}
			}
		}
		suc:;
		{
			for(int i=0;i<2;i++){
				for(int j=0;j<2;j++){
					if(o.y+i>=8 || o.x+j>=8)goto fail1;
					if(data[o.y+i][o.x+j]!='1')goto fail1;
				}
			}
			cout<<"A"<<endl;
			continue;
			fail1:;
		}
		{
			for(int i=0;i<4;i++){
				if(o.y+i>=8)goto fail2;
				if(data[o.y+i][o.x]!='1')goto fail2;
			}
			cout<<"B"<<endl;
			continue;
			fail2:; 
		}
		{
			for(int i=0;i<4;i++){
				if(o.x+i>=8)goto fail3;
				if(data[o.y][o.x+i]!='1')goto fail3;
			}
			cout<<"C"<<endl;
			continue;
			fail3:;
		}
		{
			if(o.y+2>=8 || o.x-1<=0)goto fail4;
			if(data[o.y+1][o.x]!='1')goto fail4;
			if(data[o.y+1][o.x-1]!='1')goto fail4;
			if(data[o.y+2][o.x-1]!='1')goto fail4;
			cout<<"D"<<endl;
			continue;
			fail4:;
		}
		{
			if(o.x+2>=8 || o.y+1>=8)goto fail5;
			if(data[o.y][o.x+1]!='1')goto fail5;
			if(data[o.y+1][o.x+1]!='1')goto fail5;
			if(data[o.y+1][o.x+2]!='1')goto fail5;
			cout<<"E"<<endl;
			continue;
			fail5:;
		}
		{
			if(o.x+1>=8 || o.y+2>=8)goto fail6;
			if(data[o.y+1][o.x]!='1')goto fail6;
			if(data[o.y+1][o.x+1]!='1')goto fail6;
			if(data[o.y+2][o.x+1]!='1')goto fail6;
			cout<<"F"<<endl;
			continue;
			fail6:;
		}
		{
			cout<<"G"<<endl;
		}
	}
}

C++: #include <iostream>
#include <string>
using namespace std;

#define SIZE 8

int main() {
	string source[SIZE];
	while (!cin.eof()) {
		for (int i = 0; i < SIZE; i++) {
			cin >> source[i];
		}

		bool map[14][14] = {false};
		int x = SIZE - 1, y = SIZE - 1;
		for (int i = 0; i < SIZE; i++) {
			for (int j = 0; j < SIZE; j++) {
				map[i + 3][j + 3] = (source[i][j] == '1' ? true : false);
				if (source[i][j] == '1' && j < x && i < y) {
					x = j;
					y = i;
				}
			}
		}
		x += 3;
		y += 3;

		if (map[y + 1][x + 1]) {
			if (map[y][x + 1] && map[y + 1][x]) {
				cout << "A";
			} else if (map[y + 2][x + 1] && map[y + 1][x]) {
				cout << "F";
			} else if (map[y + 1][x + 2] && map[y][x + 1]) {
				cout << "E";
			}
		}
		if (map[y - 1][x - 1]) {
			if (map[y][x + 1] && map[y + 1][x]) {
				cout << "G";
			} else if (map[y + 2][x - 1] && map[y + 1][x]) {
				cout << "D";
			}
		}
		if (map[y + 1][x] && map[y + 2][x] && map[y + 3][x]) {
			cout << "B";
		}
		if (map[y][x + 1] && map[y][x + 2] && map[y][x + 3]) {
			cout << "C";
		}
		cout << endl;
	}
	return 0;
}