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(), "")
		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++: #include <vector>
#include <iostream>
#include <utility>
#include <algorithm>
#include <string>
#include <deque>
#include <queue>
#include <tuple>
#include <queue>
#include <functional>
#include <cmath>
#include <iomanip>
#include <map>
#include <set>
#include <numeric>
#include <unordered_map>
#include <unordered_set>
#include <complex>
#include <iterator>
#include <array>
#include <memory>
#include <stack>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define all(in) in.begin(), in.end()
template<class T, class S> void cmin(T &a, const S &b) { if (a > b)a = b; }
template<class T, class S> void cmax(T &a, const S &b) { if (a < b)a = b; }
#define MAX 9999999
using namespace std;
typedef pair<int, int> pii;
typedef pair<double,double>pdd;
typedef pair<ll,ll>pll;
int main(){
    char tiya[8][8];
    while(true){
    if(cin.eof())break;
        cin>>tiya[0][0];
        if(tiya[0][0]=='\0')cin>>tiya[0][0];
    vector<pii>gotiusa;
    rep(i,8)rep(j,8){
        if(i==0&&j==0)continue;
        cin>>tiya[i][j];
        if(tiya[i][j]=='1')gotiusa.push_back(pii(i,j));
    }
    int tate=0;
    int yoko=0;
    pii t=pii(-INF,INF),y=pii(-INF,INF);
    rep(i,gotiusa.size()){
        cmax(t.first,gotiusa[i].first);
        cmin(t.second,gotiusa[i].first);
        cmax(y.first,gotiusa[i].second);
        cmin(y.second,gotiusa[i].second);
    }
    tate=t.first-t.second;
    yoko=y.first-y.second;
    if(tate==3) puts("B");
    else if(yoko==3) puts("C");
    else if(yoko==1&&tate==1)puts("A");
    else if(tate==2&&yoko==1){
        int a = 0,b = 0;
        rep(i,gotiusa.size()){
            if(t.first==gotiusa[i].first)a=gotiusa[i].second;
            else if(t.second==gotiusa[i].first)b=gotiusa[i].second;
        }
            (a>b ? puts("D"):puts("F"));
    }
    else if(tate==1&&yoko==2){
        int a = 0,b = 0;
        rep(i,gotiusa.size()){
            if(y.first==gotiusa[i].second)a=gotiusa[i].first;
            else if(y.second==gotiusa[i].second)b=gotiusa[i].first;
        }
            (a>b ? puts("E"):puts("G"));
        }
    }
    return 0;
}

C++: #include<cstdio>
#include<cmath>
#include <stdlib.h>

float spase(float a,float b,float c){
	return sqrt((a+b+c)*(b-a+c)*(a-b+c)*(a+b-c));
}

int main(){
	int b[9][9],i,j,a[8];
	for(i=0;i<8;i++){
		b[i][8]=0;
		b[8][i]=0;
	}
	while( scanf("%d",&a[0]) != EOF ){
		for(i=1;i<8;i++){
			scanf("%d",&a[i]);
				
		}
		for(j=0;j<8;j++){
			for(i=0;i<8;i++){
				b[i][7-j]=a[i]%10;
				a[i] /= 10;
			}
		}
		for(i=0;b[i/8][i%8]==0;i++){
		}
		j=i%8;
		i=i/8;
		if(b[i+1][j]&&b[i][j+1]&&b[i+1][j+1]){
			printf("A\n");
		}
		if(b[i+1][j]&&b[i+2][j]&&b[i+3][j]){
			printf("B\n");
		}
		if(b[i][j+1]&&b[i][j+2]&&b[i][j+3]){
			printf("C\n");
		}
		if(b[i+1][j]&&b[i+1][j-1]&&b[i+2][j-1]){
			printf("D\n");
		}
		if(b[i][j+1]&&b[i+1][j+1]&&b[i+1][j+2]){
			printf("E\n");
		}
		if(b[i+1][j]&&b[i+1][j+1]&&b[i+2][j+1]){
			printf("F\n");
		}
		if(b[i+1][j]&&b[i+1][j-1]&&b[i][j+1]){
			printf("G\n");
		}
	}
	return 0;
}

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

#define rep(i,n) for(int i = 0 ; i < n ;i++ )
using namespace std;

int main(){
 char  ma[8][8];
  while(!cin.eof()){
    rep(i,8){
      rep(j,8){
ma[i][j]='0';
      }
    }
    rep(i,8){
      rep(j,8){
	cin >> ma[i][j];

      }
    }
    rep(i,8){
      rep(j,8){
	if(ma[i][j]=='1'){
	  if(ma[i][j+1] == '1' && ma[i+1][j+1] == '1'&& i+1 < 8&&j+1 < 8 ){
	    cout << 'A' << endl;
	    goto f;
	  }else if(ma[i+3][j] == '1' &&i+3 < 8){
	    cout << 'B' << endl;
	    goto f;
	  }else if(ma[i][j+3] == '1'&& j+3 < 8){
	    cout << 'C' << endl;
	    goto f;
	  }else if(ma[i+3][j-1] == '1' && i+3 < 8 && 0 < j-1){
	    cout << 'D' << endl;
	    goto f;
	  }else if(ma[i+1][j+3] == '1' && i+1<8 && j+3 < 8){
	    cout << 'E' << endl;
	    goto f;
	  }else if(ma[i+1][j+3] == '1' && i+1 < 8&& j+3 < 8){
	    cout << 'F' << endl;
	    goto f;
	  }else if(ma[i][j+1] == '1' && ma[i+1][j-1] == '1' && j+1 < 8 && i+1 < 8 && 0<j-1 ){
	    cout << 'G' << endl;
	    goto f;
	  }
	}
      }
    }
  f:
  }
  return 0;
}