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 <cctype>
using  namespace std;

int main(){
	char area[8][8];
	char c;
	while(cin >> c){
		while(!isalnum(c)) cin >> c;
		for(int i = 0; i < 8; i++){
			for(int j = 0; j < 8; j++){
				area[i][j] = c;
				if(i ==  7 && j == 7) break;
				cin >> c;
			}
		}
		for(int i = 0; i < 8; i++){
			for(int j = 0; j < 8; j++){
				if(area[i][j] == '1'){
					if(i+1 < 8 && area[i+1][j] == '1'){
						if(i+2 < 8 && area[i+2][j] == '1'){
							if(i+3 < 8 && area[i+3][j] == '1'){
								cout << "B";
							}
						}
						if(j+1 < 8 && area[i+1][j+1] == '1'){
							if(i+2 < 8 && area[i+2][j+1] == '1'){
								cout << "F";
							}
							if(area[i][j+1] == '1'){
								cout << "A";
							}
						}
						if(j+1 < 8 && area[i][j+1] == '1'){
							if(j-1 >= 0 && area[i+1][j-1] == '1'){
								cout << "G";
							}
						}
						if(j+1 < 8 && area[i][j+1] == '1'){
							if(i-1 >= 0 && area[i-1][j+1] == '1'){
								cout << "D";
							}
						}
					}else if(j+1 < 8 && area[i][j+1] == '1'){
						if(j+2 < 8 && area[i][j+2] == '1'){
							if(j+3 < 8 && area[i][j+3] == '1'){
								cout <<"C";
							}
						}
						if(i+1 < 8 && area[i+1][j+1] == '1'){
							if(j+2 < 8 && area[i+1][j+2] == '1'){
								cout << "E";
							}
						}
					}
				}
			}
		}
		cout << endl;
	}
	return 0;
}

C++: #include <iostream>
#include<cstdio>
#include<cmath>
using namespace std;
char s[15][15];
char solve(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){
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()){
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 ans;
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){
ans=solve(i,j);
cout<<ans<<endl;
solved=false;
}
}
}
}
return 0;
}

C++: #include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <string>
#include <cstring>
#include <complex>
#include <ctime>
#include <cstdlib>

using namespace std;

inline int to_int(string s) {int v; istringstream sin(s); sin >> v; return v;}
template<class T> inline string to_str(T x) {ostringstream sout; sout << x; return sout.str();}

typedef long long ll;

int main()
{
	char ans = '0', wk;
	int F[16][16];
	while(cin >> wk)
	{
		if(wk == '\n')
		{
			continue;
		}
		F[0][0] = wk - '0';
		ans = '0';

		for(int i = 0; i < 8; i++)
		{
			for(int j = 0; j < 8; j++)
			{
				if(i == 0 && j == 0)
					continue;
				cin >> wk;
				F[i][j] = wk - '0';
			}
		}

		for(int i = 0; i < 8; i++)
		{
			for(int j = 0; j < 8; j++)
			{
				if(F[i][j] && F[i][j+1] && F[i+1][j] && F[i+1][j+1])
				{
					ans = 'A';
					break;
				}
				if(F[i][j] && F[i+1][j] && F[i+2][j] && F[i+3][j])
				{
					ans = 'B';
					break;
				}
				if(F[i][j] && F[i][j+1] && F[i][j+2] && F[i][j+3])
				{
					ans = 'C';
					break;
				}
				if(F[i][j] && F[i+1][j] && F[i+1][j-1] && F[i+2][j-1])
				{
					ans = 'D';
					break;
				}
				if(F[i][j] && F[i][j+1] && F[i+1][j+1] && F[i+1][j+2])
				{
					ans = 'E';
					break;
				}
				if(F[i][j] && F[i+1][j] && F[i+1][j+1] && F[i+2][j+1])
				{
					ans = 'F';
					break;
				}
				if(F[i][j] && F[i][j+1] && F[i-1][j+1] && F[i-1][j+2])
				{
					ans = 'G';
					break;
				}
			}
			if(ans != '0')
			{
				break;
			}
		}

		cout << ans << endl;
	}
}

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

int main()
{
  while (true)
  {
    char board[8][8];
    for (int i=0; i<8; i++)
    {
      for (int j=0; j<8; j++)
      {
        cin >> board[i][j];
      }
    }

    bool flag = false;
    for (int i=0; i<8; i++)
    {
      for (int j=0; j<8; j++)
      {
        if ( board[i][j] == '1' )   //  ブロックがあれば
        {
          if ( board[i+3][j] == '1' )
          {
            cout << 'B' << endl;
          }
          else if ( board[i][j+3] == '1' )
          {
            cout << 'C' << endl;
          }
          else if ( board[i+2][j-1] == '1' )
          {
            cout << 'D' << endl;
          }
          else if ( board[i+1][j+2] == '1' )
          {
            cout << 'E' << endl;
          }
          else if ( board[i+2][j+1] == '1' )
          {
            cout << 'F' << endl;
          }
          else if ( board[i+1][j-1] == '1' )
          {
            cout << 'G' << endl;
          }
          else
          {
            cout << 'A' << endl;
          }
          flag = true;
        }
        if (flag) break;
      }
      if (flag) break;
    }

    char dummy;
    cin >> noskipws;
    cin >> dummy >> dummy;
    cin >> skipws;
    if ( cin.eof() ) break;
  }
}