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)
	}
}

C++: #include <bits/stdc++.h>
using namespace std;

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

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

char n[12][12];
char figure[7][4][5] = {
	{"1100","1100","0000","0000"},
	{"1000","1000","1000","1000"},
	{"1111","0000","0000","0000"},
	{"0100","1100","1000","0000"},
	{"1100","0110","0000","0000"},
	{"1000","1100","0100","0000"},
	{"0110","1100","0000","0000"}
};


void clear(){
	for(int i=0; i<12; i++)
			n[i][8]='0';
}

int main(){
	for(int i=0; i<12; i++)
		for(int j=0; j<12; j++)
			n[i][j]='0';

	while(~scanf("%8s\n%8s\n%8s\n%8s\n%8s\n%8s\n%8s\n%8s\n\n", n[0], n[1], n[2], n[3], n[4], n[5], n[6], n[7])){
		clear();
		for(int i=0; i<7; i++){
			for(int j=0; j<8; j++){
				for(int k=0; k<8; k++){
					bool flag=true;
					
					for(int x=0; x<4; x++){
						for(int y=0; y<4; y++){
							if(figure[i][x][y] != n[j+x][k+y]) flag = false;
						}
					}
					
					if(flag){
						cout << (char)('A'+i) << endl;
					}

				}
			}
		}
	}
	return 0;
}

C++: #include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip> 
#include <complex> 
#include <string>
#include <vector> 
#include <list>
#include <deque> 
#include <stack> 
#include <queue> 
#include <set>
#include <map>
#include <bitset>
#include <functional>
#include <utility>
#include <algorithm> 
#include <numeric> 
#include <typeinfo> 
#include <cstdio>
#include <cstdlib> 
#include <cstring>
#include <cmath>
#include <climits> 
#include <ctime>

using namespace std;

char field[11][11],field2[11][11];

int main(void){
	while(1){
		int i,j;
		bool flag=false;
		for(j=0;j<11;j++){
			for(i=0;i<11;i++){
				field[i][j]='\0';
				field2[i][j]='\0';
			}
		}
		for(i=0;i<8;i++){
			if(scanf("%s",field[i])==EOF){
				flag=true;
				break;
			}
			if(flag)break;
		}
		for(j=0;j<8;j++){
			for(i=0;i<8;i++){
				field2[i][j]=field[j][i];
			}
		}
		for(j=0;j<8;j++){
			for(i=0;i<8;i++){
				if(field2[i][j]=='1' && field2[i+1][j]=='1' && field2[i][j+1]=='1' && field2[i+1][j+1]=='1')printf("A\n");
				if(field2[i][j]=='1' && field2[i][j+1]=='1' && field2[i][j+2]=='1' && field2[i][j+3]=='1')printf("B\n");
				if(field2[i][j]=='1' && field2[i+1][j]=='1' && field2[i+2][j]=='1' && field2[i+3][j]=='1')printf("C\n");
				if(field2[i+1][j]=='1' && field2[i+1][j+1]=='1' && field2[i][j+1]=='1' && field2[i][j+2]=='1')printf("D\n");
				if(field2[i][j]=='1' && field2[i+1][j]=='1' && field2[i+1][j+1]=='1' && field2[i+2][j+1]=='1')printf("E\n");
				if(field2[i][j]=='1' && field2[i][j+1]=='1' && field2[i+1][j+1]=='1' && field2[i+1][j+2]=='1')printf("F\n");
				if(field2[i][j+1]=='1' && field2[i+1][j+1]=='1' && field2[i+1][j]=='1' && field2[i+2][j]=='1')printf("G\n");
			}
		}
	}
	return 0;
}

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


int main(int argc,char* argv[]){
		std::string ans[7] ={"1100000011","1000000010000000100000001","1111","1000000110000001","11000000011","100000001100000001","110000011"};
		std::string alpha[7]={"A","B","C","D","E","F","G"};
		std::string prob[8];
		std::string problem;

		while(std::cin >> prob[0]){
						for(int a=1; a < 8; a++){
										std::cin >> prob[a];
						}
						for(int b=0; b < 8; b++){
										problem = problem + prob[b];
						}
						for(int c=0; c < 7; c++){
										std::string::size_type index = problem.find(ans[c]);
										if(index != std::string::npos){
														std::cout << alpha[c] << std::endl;
										}
						}
						problem ="";
		}
}

C++: #include<stdio.h>

char grid[8][8];
int vecx[7][3] = { { 0, 1, 1 }, { 0, 0, 0 }, { 1, 2, 3 }, { 0, -1, -1 }, { 1, 1, 2 }, { 0, 1, 1 },{ 1, -1, 0 } };
int vecy[7][3] = { { 1, 0, 1 }, { 1, 2, 3 }, { 0, 0, 0 }, { 1, 1, 2 }, { 0, 1, 1 }, { 1, 1, 2 }, { 0, 1, 1 } };

int main()
{
	while( 1 ){
	
		for( int i = 0; i < 8; i++ )if( scanf( "%s", grid[i] ) == EOF ) goto end;
	
		for( int i = 0; i < 8; i++ ){
		 	for( int j = 0; j < 8; j++ ){
				if( grid[i][j] == '1' ){
					for( int k = 0; k < 7; k++ ){
						if( grid[i+vecy[k][0]][j+vecx[k][0]] == '1' 
						 && grid[i+vecy[k][1]][j+vecx[k][1]] == '1' 
						 && grid[i+vecy[k][2]][j+vecx[k][2]] == '1' )
							printf( "%c\n", 'A' + k );	
					}
				}
			}
		}
	}

end:

 	return 0;
}