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<string>

using namespace std;
int main(){
	
	while(1){
	string str[8];
	for(int i =0;i<8;i++)
		cin >> str[i];
	
	bool stop = false;
	for(int i=0;i<8;i++){
	for(int k=0;k<8;k++){
	if(str[i][k] == '1'){
		if(str[i][k+1] == '1' && str[i+1][k+1] == '1'&& str[i+1][k] == '1' ){
		cout << "A" << endl;  stop = true; break;
		} else if(str[i+1][k] == '1' && str[i+2][k] == '1'&& str[i+3][k] == '1' ){
		cout << "B" << endl; stop = true; break;
		} else if(str[i][k+1] == '1' && str[i][k+2] == '1'&& str[i][k+3] == '1' ){
		cout << "C" << endl;  stop = true; break;
		} else if(str[i+1][k] == '1' && str[i+1][k-1] == '1'&& str[i+2][k-1] == '1' ){
		cout << "D" << endl;  stop = true; break;
		} else if(str[i][k+1] == '1' && str[i+1][k+1] == '1'&& str[i+1][k+2] == '1' ){
		cout << "E" << endl;  stop = true; break;
		} else if(str[i+1][k] == '1' && str[i+1][k+1] == '1'&& str[i+2][k+1] == '1' ){
		cout << "F" << endl;  stop = true; break;
		} else if(str[i][k+1] == '1' && str[i+1][k] == '1'&& str[i+1][k-1] == '1' ){
		cout << "G" << endl;  stop = true; break;
		}
	
	}
	
	}
	if(stop == true) break;
	}
	if(cin.eof()) return 0;
	
	}
	
}

C++: #include <stdio.h>

int main(void) {
  char s[8][10];
  int i, j, k, l;
  int dx[7][3] = {
    {1, 1, 0},
    {0, 0, 0},
    {1, 2, 3},
    {0, -1, -1},
    {1, 1, 2},
    {0, 1, 1},
    {1, -1, 0}
  }, dy[7][3] = {
    {0, 1, 1},
    {1, 2, 3},
    {0, 0, 0},
    {1, 1, 2},
    {0, 1, 1},
    {1, 1, 2},
    {0, 1, 1}
  };
  while(scanf("%s", s[0]) != EOF) {
    for(i = 1; i < 8; ++i) scanf("%s", s[i]);
    int t = 1;
    for(i = 0; i < 8; ++i) {
      for(j = 0; j < 8; ++j) {
        if(s[i][j] == '1') {
          for(k = 0; k < 7; ++k) {
            for(l = 0; l < 3; ++l) {
              if(i + dy[k][l] < 0 || i + dy[k][l] > 8 || j + dx[k][l] < 0 || j + dx[k][l] > 8 || s[i + dy[k][l]][j + dx[k][l]] == '0') break;
            }
            if(l == 3) {
              printf("%c\n", 'A' + k);
              break;
            }
          }
          t = 0;
          break;
        }
      }
      if(!t) break;
    }
  }
  return 0;
}

C++: #include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <map>
#include <queue>
#include <cstdlib>
#include <algorithm>
#include <iterator>
#include <stack>
typedef long long int lli;
using namespace std;

int dx[7][4]={{0,0,1,1},{0,0,0,0},{0,1,2,3},{0,0,-1,-1},{0,1,1,2},{0,0,1,1},{0,-1,0,1}};
int dy[7][4]={{0,1,1,0},{0,1,2,3},{0,0,0,0},{0,1,1,2},{0,0,1,1},{0,1,1,2},{0,1,1,0}};
string MAP[8];
string ans="ABCDEFG";

int main(){
	while(1){
	for(int i=0; i<8; ++i){
		if(!(cin >> MAP[i])){
			return 0;
		}
	}
	for(int i=0; i<8; ++i){
		for(int j=0; j<8; ++j){
			if(MAP[i][j]=='1'){
				for(int k=0; k<7; ++k){
					bool ok=true;
					for(int l=0; l<4; ++l){
						int nx=j+dx[k][l];
						int ny=i+dy[k][l];
						if((0<=nx&&nx<8&&0<=ny&&ny<8&&MAP[ny][nx]!='1')||(nx<0||8<=nx||ny<0||8<=ny)){
							ok=false;
							break;
						}
					}
					if(ok){
						cout << ans[k] << "\n";
						break;
					}
				}
			}
		}
	}
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
	string s;
	while(cin >> s){
		bool a[10][10] = {0};
		for(int j = 1; j <= 8; j++){
			a[1][j] = s[j-1] - 48;
		}
		for(int i = 2; i <= 8; i++){
			cin >> s;
			for(int j = 1; j <= 8; j++){
				a[i][j] = s[j-1] - 48;
			}
		}
		bool f = true;
		for(int i = 1; i <= 8 && f; i++){
			for(int j = 1; j <= 8; j++){
				if(a[i][j]){
					if(a[i][j+1] && a[i+1][j] && a[i+1][j+1]) cout << "A" << endl;
					else if(a[i+1][j] && a[i+2][j] && a[i+3][j]) cout << "B" << endl;
					else if(a[i][j+1] && a[i][j+2] && a[i][j+3]) cout << "C" << endl;
					else if(a[i+1][j-1] && a[i+1][j] && a[i+2][j-1]) cout << "D" << endl;
					else if(a[i][j+1] && a[i+1][j+1] && a[i+1][j+2]) cout << "E" << endl;
					else if(a[i][j+1] && a[i+1][j-1] && a[i+1][j]) cout << "G" << endl;
					f = false;
					break;
				}
			}
		}
	}
	return 0;
}

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

using namespace std;

int A[7][4][4]={
  
  {
    {1,1,0,0},
    {1,1,0,0},
    {0,0,0,0},
    {0,0,0,0},
  },
  
  {
    {1,0,0,0},
    {1,0,0,0},
    {1,0,0,0},
    {1,0,0,0},
  },
  
  {
    {1,1,1,1},
    {0,0,0,0},
    {0,0,0,0},
    {0,0,0,0},
  },
  
  {
    {0,1,0,0},
    {1,1,0,0},
    {1,0,0,0},
    {0,0,0,0},
  },
  
  {
    {1,1,0,0},
    {0,1,1,0},
    {0,0,0,0},
    {0,0,0,0},
  },
  
  {
    {1,0,0,0},
    {1,1,0,0},
    {0,1,0,0},
    {0,0,0,0},
  },
  
  {
    {0,1,1,0},
    {1,1,0,0},
    {0,0,0,0},
    {0,0,0,0},
  },
},
  
  a[12][12];

string s="ABCDEFG";

void check(){


  for(int n=0;n<7;n++){

    for(int i=0;i<8;i++){
      for(int j=0;j<8;j++){

	bool fg=true;
	for(int k=0;k<4;k++){
	  for(int l=0;l<4;l++){
	    if(a[i+k][j+l]!=A[n][k][l]){
	      fg=false;
	      break;
	    }
	    if((i+k<0||i+k>7||j+l<0||j+k>7)&&A[n][k][l]==1){
	      fg=false;
	      break;
	    }
	  }
	  if(!fg)break;
	}
	if(fg){
	  cout << s[n] << endl;
	  return;
	}
	fg=true;
	
      }
    }
  }

}


int main(void){

  char ch;

  while(true){

    for(int i=0;i<12;i++)
      for(int j=0;j<12;j++)
	a[i][j]=0;
    
    for(int i=0;i<8;i++){
      for(int j=0;j<8;j++){
	if(scanf(" %c",&ch)==EOF)return 0;
	a[i][j]=ch-'0';
      }
    }
    check();
  }

  return 0;
}