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
}

func main() {
	for {
		var board [][]int
		var ans string
		if board = scanBoard(); reflect.DeepEqual(board, [][]int{}) {
			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++: #define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;

//#define int long long
#define DBG 1
#define dump(o) if(DBG){cerr<<#o<<" "<<o<<endl;}
#define dumpc(o) if(DBG){cerr<<#o; for(auto &e:(o))cerr<<" "<<e;cerr<<endl;}
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define each(it,c) for(auto it=(c).begin();it!=(c).end();it++)
#define all(c) c.begin(),c.end()
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9 + 7);

signed main() {
	string s;
	while (cin >> s) {
		vector<string>v;
		v.push_back(s);
		rep(i, 0, 7) {
			string t; cin >> t;
			v.push_back(t);
		}
		char ans;
		rep(i, 0, 8) {
			rep(j, 0, 8) {
				if (v[i][j] == '1') {
					if (v[i][j + 1] == '1'&&v[i + 1][j] == '1'&&v[i + 1][j + 1] == '1')ans = 'A';
					else if (v[i + 1][j] == '1'&&v[i + 2][j] == '1'&&v[i + 3][j] == '1')ans = 'B';
					else if (v[i][j + 1] == '1'&&v[i][j + 2] == '1'&&v[i][j + 3] == '1')ans = 'C';
					else if (v[i + 1][j] == '1'&&v[i + 1][j - 1] == '1'&&v[i + 2][j - 1] == '1')ans = 'D';
					else if (v[i][j + 1] == '1'&&v[i + 1][j + 1] == '1'&&v[i + 1][j + 2] == '1')ans = 'E';
					else if (v[i + 1][j] == '1'&&v[i + 1][j + 1] == '1'&&v[i + 2][j + 1] == '1')ans = 'F';
					else if (v[i][j + 1] == '1'&&v[i + 1][j] == '1'&&v[i - 1][j - 1] == '1')ans = 'G';
					goto here;
				}
			}
		}
	here:;
		cout << ans << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <cstring>
#include <string>
using namespace std;
struct P {int x, y; char s[4][5];};
char f[8][9] = {{""}};
bool c(int x, int y, P p)
{
	int i, j;
	char t[8][9];
	for (i = 0; i < 8; i++)
		strcpy(t[i], f[i]);
	for (i = 0; i < p.y; i++)
	{
		for (j = 0; j < p.x; j++)
		{
			t[y+i][x+j] = p.s[i][j];
		}
	}
	for (i = 0; i < 8; i++)
		if (strcmp(t[i], f[i]) != 0)
		{
			return false;
		}
	return true;
}
int main()
{
	P p[7] = {2, 2, {"11", "11"},
		1, 4, {"1", "1", "1", "1"},
		4, 1, {"1111"},
		2, 3, {"01", "11", "10"},
		3, 2, {"110", "011"},
		2, 3, {"10", "11", "01"},
		3, 2, {"011", "110"}};
	int i, j, k;
	bool b;
	char res;
	string t;
	while (!cin.eof())
	{
		for (i = 0; i < 8; i++)
			cin >> f[i];
		cin.ignore();
		for (i = 0; i < 8; i++)
		{
			for (j = 0; j < 8; j++)
			{
				for (k = 0; k < 7; k++)
				{
					if (8-j >= p[k].x && 8-i >= p[k].y)
						if (b = c(j, i, p[k]))
							res = 'A' + k;
				}
				if (b) break;
			}
			if (b) break;
		}
		cout << res << endl;
	}
}

C++: #include <stdio.h>
#include <algorithm>

using namespace std;

int main(){
	char table[8][9];

	while(scanf("%s",table[0])!=EOF){
		for(int i=1; i < 8; i++){
			scanf("%s",table[i]);
		}
		bool FLG = false;
		for(int i=0; i < 8; i++){
			for(int k=0; k<8; k++){
				if(table[i][k] == '1'){
					if(i <= 6 && k <= 6 && table[i][k+1] == '1' && table[i+1][k] == '1' && table[i+1][k+1] == '1'){
						printf("A\n");
						FLG = true;
						break;
					}else if(i <= 4 && table[i+1][k] == '1' && table[i+2][k] == '1' && table[i+3][k] == '1'){
						printf("B\n");
						FLG = true;
						break;
					}else if(k <= 4 && table[i][k+1] == '1' && table[i][k+2] == '1' && table[i][k+3] == '1'){
						printf("C\n");
						FLG = true;
						break;
					}else if(i <= 5 && k >= 1 && table[i+1][k-1] == '1' && table[i+1][k] == '1' &&
							table[i+2][k-1] == '1'){
						printf("D\n");
						FLG = true;
						break;
					}else if(i <= 6 && k <= 5 && table[i][k+1] == '1' && table[i+1][k+1] == '1' &&
							table[i+1][k+2] == '1'){
						printf("E\n");
						FLG = true;
						break;
					}else if(i <= 5 && k <= 6 && table[i+1][k] == '1' && table[i+1][k+1] == '1' &&
							table[i+2][k+1] == '1'){
						printf("F\n");
						FLG = true;
						break;
					}else if(i <= 6 && k <= 6 && k >= 1 && table[i][k+1] == '1' && table[i+1][k-1] == '1' &&
							table[i+i][k] == '1'){
						printf("F\n");
						FLG = true;
						break;
					}
				}
			}
			if(FLG)break;
		}
	}


	return 0;
}

C++: #include <iostream>

using namespace std;

int main(void){
     char field[8][8];
     char tmp;
     int i,j;
	 while(1){
	   for(i=0;i<8;i++){
		 for(j=0;j<8;j++){
		   cin >> field[i][j];
		   //cout << field[i][j];
		 }
		 //cout << endl;
	   }
	   
	   //»ê¼êÌ`ÉÂ¢Ä»Ê
	   //Ü¸¶ãÌ}XðT·
	   for(i=0;i<8;i++){
		 for(j=0;j<8;j++){
		   if(field[i][j] == '1') goto NEXT;
		 }
	   }
	 NEXT:
	   //cout << i << "    " << j << endl;

     
	   if(j+3 <= 7 && field[i][j+1] == '1' && field[i][j+2] == '1' && field[i][j+3] == '1'){
		 //¡êñ
		 cout << "C" << endl;
	   }else if(i+3 <= 7 && field[i+1][j]  == '1' && field[i+2][j] == '1' && field[i+3][j] == '1'){
		 //cêñ
		 cout << "B" << endl;
	   }else if(j+1 <= 7 && i+1 <= 7 && field[i][j+1] == '1' && field[i+1][j] == '1' && field[i+1][j+1] == '1'){
		 //³û`
		 cout << "A" << endl;
	   }else if(i+2 <= 7 && j+1 <= 7 && field[i+1][j] == '1' && field[i+1][j+1]  == '1' && field[i+2][j+1] == '1'){
		 //1 0
		 //1 1
		 //0 1
		 cout << "F" << endl;
	   }else if(j-1 >= 0 && j+1 <= 7 && i+1 <= 7 && field[i][j+1] == '1' && field[i+1][j] == '1' && field[i+1][j-1] == '1'){
		 //0 1 1
		 //1 1 0
		 cout << "G" << endl;
	   }else if(j+2 <= 7 && i+1 <= 7 && field[i][j+1] == '1' && field[i+1][j+1]  == '1' && field[i+1][j+2] == '1'){
		 //1 1 0
		 //0 1 1
		 cout << "E" << endl;
	   }else{
		 cout << "D" << endl;
	   }
	   cin.ignore();
	   cin.ignore();
	   if(cin.eof()) return 0;
	 }
	 return 0;
}

C++: #include <iostream>
main(){int b[5][4],s,t,x,y;char l[8];for(;;){for(int i=0;i<20;i++)b[i%5][i/5]=0;sx=sy=9;for(y=0;y<8;y++){if(!(std::cin>>l))break;for(x=0;x<8;x++){if(l[x]=='1'){if(t==9){s=x-1;t=y;}b[x-s][y-t]=1;}}}if (y<8)break;char a='A';if(b[1][3])a='B';if(b[4][0])a='C';if(b[0][2])a='D';if(b[3][1])a='E';if(b[2][2])a='F';if(b[0][1]&&b[2][0])a='G';std::cout<<a<<"\n";}}