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 <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
#define FOR(i,a,b) for(int i=(a);i<(int)(b);i++)
#define rep(i,n) FOR(i,0,n)
#define ALL(x) (x).begin(), (x).end()
#define pb push_back

char a[10][10];

bool is_a(int i, int j) {
    return (a[i][j+1]=='1'&&a[i+1][j]=='1'&&a[i+1][j+1]=='1');
}
bool is_b(int i, int j) {
    return (a[i+1][j]=='1'&&a[i+2][j]=='1'&&a[i+3][j]=='1');
}
bool is_c(int i, int j) {
    return (a[i][j+1]=='1'&&a[i][j+2]=='1'&&a[i][j+3]=='1');
}
bool is_d(int i, int j) {
    return (a[i+1][j]=='1'&&a[i+1][j-1]=='1'&&a[i+2][j-1]=='1');
}
bool is_e(int i, int j) {
    return (a[i][j+1]=='1'&&a[i+1][j+1]=='1'&&a[i+1][j+2]=='1');
}
bool is_f(int i, int j) {
    return (a[i+1][j]=='1'&&a[i+1][j+1]=='1'&&a[i+2][j+1]=='1');
}
bool is_g(int i, int j) {
    return (a[i][j+1]=='1'&&a[i+1][j]=='1'&&a[i+1][j-1]=='1');
}

int main() {
    while(cin >> a[0]) {
        FOR(i,1,8) cin >> a[i];
        //rep(i,8) cout << a[i] << endl;
        rep(i,8) rep(j,8) {
            if(a[i][j] == '1') {
                if(is_a(i,j)) cout<<"A"<<endl;
                if(is_b(i,j)) cout<<"B"<<endl;
                if(is_c(i,j)) cout<<"C"<<endl;
                if(is_d(i,j)) cout<<"D"<<endl;
                if(is_e(i,j)) cout<<"E"<<endl;
                if(is_f(i,j)) cout<<"F"<<endl;
                if(is_g(i,j)) cout<<"G"<<endl;
            }
        }
    }

    return 0;
}

C++: #include<iostream>
#include<vector>
#include<array>
#include<string>
#include<sstream>
#define _X_ 0
#define _Y_ 1
int main()
{
	while (true)
	{
		std::vector<std::array<int, 2>>p;
		p.reserve(4);
		for (int i = 0; i < 8; i++)
		{
			std::string temp;
			std::cin >> temp;
			std::stringstream st(temp);
			for (int j = 0; j < 8; j++)
			{
				char foo;
				st >> foo;
				if (foo == '1')
				{
					p.push_back({ j, i });
				}
			}
		}
		if (p[0][_Y_] == p[1][_Y_])
		{
			if (p[0][_X_] == p[2][_X_])
			{
				std::cout << 'A' << std::endl;
			}
			else if (p[0][_Y_] == p[2][_Y_])
			{
				std::cout << 'C' << std::endl;
			}
			else if (p[1][_X_] == p[2][_X_])
			{
				std::cout << 'E' << std::endl;
			}
			else if (p[0][_X_] == p[3][_X_])
			{
				std::cout << 'G' << std::endl;
			}
		}
		else
		{
			if (p[0][_X_] == p[3][_X_])
			{
				std::cout << 'B' << std::endl;
			}
			else if (p[0][_X_] > p[3][_X_])
			{
				std::cout << 'D' << std::endl;
			}
			else
			{
				std::cout << 'F' << std::endl;
			}
		}
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int(i) = 0;(i)<(n);(i)++)
#define pb push_back
#define mp make_pair
#define All(X) X.begin(),X.end()

int main(){
	vector<int> vx, vy;
	while (1){
		REP(i, 8){
			string str;
			cin >> str;
			if (cin.eof()){
				return 0;
			}
			REP(j, 8){
				if (str[j] == '1'){
					vx.pb(i);
					vy.pb(j);
				}
			}
		}
		char ans = 'G';
		if (vx[0] == vx[1] && vy[0] == vy[2]) ans == 'A';
		if (vy[0] == vy[1] && vy[0] == vy[2] && vy[0] == vy[3]) ans = 'B';
		if (vx[0] == vx[1] && vx[0] == vx[2] && vx[0] == vx[3]) ans = 'C';
		if (vx[1] == vx[2] && vy[1] == vy[3] && vy[0] == vy[2]) ans = 'D';
		if (vx[0] == vx[1] && vx[2] == vx[3] && vy[1] == vy[2] && vy[0] + 2 == vy[3]) ans = 'E';
		if (vx[1] == vx[2] && vy[0] == vy[1] && vy[2] == vy[3]) ans = 'F';
		cout << ans << endl;
	}
}

C++:  
 #include<iostream>
 #include<stdio.h>
 #include<string>
 #include<math.h>
 #include<iomanip>
 #include<algorithm>
 #include<string.h>
 #include<cctype>
 #include<map>
 #include<set>
 #include<vector>
 #include<sstream>
 #include<stack>
 #include<queue>
 
 using namespace std;

 char arr[8][8];
 
 int main()
 {
   while(cin>>arr[0][0])
   {
     int x[4],y[4];
     int cnt1,cnt2;
     cnt1=cnt2=0;
     if(arr[0][0]=='1') 
     {
       x[cnt1++]=0;
       y[cnt2++]=0;                   
     }
     for(int i=0;i<8;i++)
     {
       for(int j=0;j<8;j++)
       {
           if(i==0&&j==0) continue;
           else
           {
             cin>>arr[i][j];
             if(arr[i][j]=='1')
             {
               x[cnt1++]=j;
               y[cnt2++]=i;                
             }
           }    
                 
       }        
     }             
     if(y[0]==y[1]&&y[2]==y[3]&&x[1]==x[0]+1&&x[3]==x[2]+1&&y[2]==y[0]+1&&x[3]==x[0]+1) cout<<"A"<<endl;
     else if(x[0]==x[1]&&x[1]==x[2]&&x[2]==x[3]) cout<<"B"<<endl;
     else if(y[0]==y[1]&&y[1]==y[2]&&y[2]==y[3]) cout<<"C"<<endl;
     else if(y[1]==y[2]&&y[3]==y[0]+2) cout<<"D"<<endl;
     else if(x[1]==x[2]&&(x[3]==x[0]+2)) cout<<"E"<<endl;
     else if(y[1]==y[2]&&y[3]==y[0]+2) cout<<"F"<<endl;
     else cout<<"G"<<endl;        
   }
   //while(1);
   return 0;
 }

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

int main()
{
	typedef std::map<std::string, char> FigureToIdent;
	FigureToIdent figure_to_idnt;
	figure_to_idnt.insert(std::make_pair("1100000011", 'A'));
	figure_to_idnt.insert(std::make_pair("1000000010000000100000001", 'B'));
	figure_to_idnt.insert(std::make_pair("1111", 'C'));
	figure_to_idnt.insert(std::make_pair("1000000110000001", 'D'));
	figure_to_idnt.insert(std::make_pair("11000000011", 'E'));
	figure_to_idnt.insert(std::make_pair("100000001100000001", 'F'));
	figure_to_idnt.insert(std::make_pair("110000011", 'G'));

	std::string input;
	while (getline(std::cin, input)) {
		if (input == "") {
			getline(std::cin, input);
		}
		for (std::uint16_t i = 1; i < 8; ++i) {
			std::string temp;
			getline(std::cin, temp);
			input += temp;
		}

		for (auto const& value : figure_to_idnt) {
			if (input.find(value.first) != std::string::npos) {
				std::cout << value.second << std::endl;
				break;
			}
		}
	}

	return 0;
}