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)
		fmt.Scanln()
	}
}

C++: #include<iostream>
#include<cstring>
using namespace std;
int x[13][13]; char a;
int main() {
	while (cin >> a) {
		memset(x, 0, sizeof(x));
		if (a == '0') { 
			x[1][1] = 0; 
		}
		if (a == '1') { 
			x[1][1] = 1; 
		}
		for (int i = 1; i <= 8; i++) {
			for (int j = 1; j <= 8; j++) {
				if (i + j > 2) {
					cin >> a; if (a == '0') { x[i][j] = 0; }
					else { x[i][j] = 1; }
				}
			}
		}
		for (int i = 1; i <= 8; i++) {
			for (int j = 1; j <= 8; j++) {
				if (x[i][j] == 1) {
					if (x[i + 1][j] == 1 && x[i][j + 1] == 1 && x[i + 1][j + 1] == 1) {
						cout << 'A' << endl; goto Exit;
					}
					if (x[i + 1][j] == 1 && x[i + 2][j] == 1 && x[i + 3][j] == 1) {
						cout << 'B' << endl; goto Exit;
					}
					if (x[i][j + 1] == 1 && x[i][j + 2] == 1 && x[i][j + 3] == 1) {
						cout << 'C' << endl; goto Exit;
					}
					if (x[i + 1][j - 1] == 1 && x[i + 1][j] == 1 && x[i + 2][j - 1] == 1) {
						cout << 'D' << endl; goto Exit;
					}
					if (x[i][j + 1] == 1 && x[i + 1][j + 1] == 1 && x[i + 1][j + 2] == 1) {
						cout << 'E' << endl; goto Exit;
					}
					if (x[i + 1][j] == 1 && x[i + 1][j + 1] == 1 && x[i + 2][j + 1] == 1) {
						cout << 'F' << endl; goto Exit;
					}
					if (x[i][j + 1] == 1 && x[i + 1][j - 1] == 1 && x[i + 1][j] == 1) {
						cout << 'G' << endl; goto Exit;
					}
				}
			}
		}
	Exit:;
	}
}

C++: #include<bits/stdc++.h>
#define rep(i,n)for(int i=0;i<n;i++)
using namespace std;

char s[18][18];
string buf;
int main(){
	do{
		memset(s,0,sizeof(s));
		for(int i=1;i<=8;i++)scanf("%s",s[i]+1);
		for(int i=1;i<=8;i++){
			for(int j=1;j<=8;j++){
				if(s[i][j]!='1')continue;
				if(s[i][j+1]=='1'&&s[i+1][j+1]=='1'&&s[i+1][j]=='1'){puts("A");goto p;}
				if(s[i+1][j]=='1'&&s[i+2][j]=='1'&&s[i+3][j]=='1'){puts("B");goto p;}
				if(s[i][j+1]=='1'&&s[i][j+2]=='1'&&s[i][j+3]=='1'){puts("C");goto p;}
				if(s[i+1][j-1]=='1'&&s[i+1][j]=='1'&&s[i+2][j-1]=='1'){puts("D");goto p;}
				if(s[i][j+1]=='1'&&s[i+1][j+1]=='1'&&s[i+1][j+2]=='1'){puts("E");goto p;}
				if(s[i+1][j]=='1'&&s[i+1][j+1]=='1'&&s[i+2][j+1]=='1'){puts("F");goto p;}
				if(s[i][j+1]=='1'&&s[i+1][j-1]=='1'&&s[i+1][j]=='1'){puts("G");goto p;}
			}
		}
		p:;
	}while(getline(cin,buf));
	return 0;
}

C++: #include<cstdio>
#include<cmath>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<iostream>

using namespace std;

char s[15][15];

char Solution(int i, int j)
{
    if(s[i][j]=='1' && s[i + 1][j] == '1' && s[i][j + 1] == '1' && s[i + 1][j + 1] == '1')
    {
        return 'A';
    }
    
    if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 2][j] == '1' && s[i + 3][j] == '1')
    {
        return 'B';
    }
    
    if(s[i][j] == '1' && s[i][j + 1] == '1' && s[i][j + 2] == '1' && s[i][j + 3] == '1')
    {
        return 'C';
    }
    
    if(s[i][j] == '1' && s[i][j + 1] == '1' && s[i + 1][j + 1] == '1' && s[i + 1][j + 2] == '1')
    {
        return 'E';
    }
    
    if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 1][j + 1] == '1'&&s[i + 2][j + 1] == '1')
    {
        return 'F';
    }
    
    if(j > 0)  // can not start from j = 0
    {
        if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 1][j - 1] == '1' && s[i + 2][j - 1] == '1')
        {
            return 'D';
        }
        
        if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 1][j - 1] == '1' && s[i][j + 1] == '1')
        {
            return 'G';
        }
    }
    
    return 0;
}

int main()
{
    while(!cin.eof())  // tests for end-of-file
    {
        
        for(int i = 0; i < 15; i++)
        {
            for(int j = 0; j < 15; j++)
            {
                s[i][j] = '0';
            }
        }
        
        for(int i = 0; i < 8; i++)
        {
            cin>>s[i];
        }
        
        char figure;
        
        bool solved = true;
        
        for(int i=0;i<8;i++)
        {
            for(int j=0;j<8;j++)
            {
                if(s[i][j]!='1')
                {
                    continue;
                }
                
                if(solved)
                {
                    figure = Solution(i, j);
                    
                    cout<<figure<<endl;
                    
                    solved = false;
                }
            }
        }
    }
    return 0;
}

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

/*
0123
456
78
9
*/
const int data[7][10] = {
						{1, 1, 0, 0, 1, 1, 0, 0, 0, 0},
						{1, 0, 0, 0, 1, 0, 0, 1, 0, 1},
						{1, 1, 1, 1, 0, 0, 0, 0, 0, 0},
						{0, 1, 0, 0, 1, 1, 0, 1, 0, 0},
						{1, 1, 0, 0, 0, 1, 1, 0, 0, 0},
						{1, 0, 0, 0, 1, 1, 0, 0, 1, 0},
						{0, 1, 1, 0, 1, 1, 1, 0, 0, 0}
						};

const int change[10][2] = {{0, 0}, {1, 0}, {2, 0}, {3, 0}, {0, 1}, {1, 1}, {2, 1}, {0, 3}, {1, 3}, {0, 4}};

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	while(1){
		int c[15][15];
		for(int i = 0; i < 15; ++i){
			for(int j = 0; j < 15; ++j){
				c[j][i] = 0;
			}
		}

		for(int i = 0; i < 8; ++i){
			for(int j = 0; j < 8; ++j){
				char c0;
				cin >> c0;
				c[j][i] = (c0 == '0') ? 0 : 1;
			}
		}

		if(cin.eof()){
			break;
		}

		for(int i = 0; i < 8; ++i){
			for(int j = 0; j < 8; ++j){
				for(int k = 0; k < 7; ++k){
					bool check = true;
					for(int l = 0; l < 10; ++l){
						if(c[j + change[l][0]][i + change[l][1]] != data[k][l]){
							check = false;
							break;
						}
					}
					if(check){
						cout << char('A' + k) << endl;
						break;
					}
				}
			}
		}
	}

	return 0;
}