Language: C++

#include<iostream>
#include<cstdio>
using namespace std;

int main(){
	char n[12][12];
	char figure[7][4][4] = {
		{"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"}
	};

	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])){
		for(int i=0; i<8; i++)
			for(int j=0; j<8; j++)
				cin >> n[i][j];

		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;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:18: error: initializer-string for 'char [4]' is too long [-fpermissive]
    8 |                 {"1100","1100","0000","0000"},
      |                  ^~~~~~
a.cc:8:25: error: initializer-string for 'char [4]' is too long [-fpermissive]
    8 |                 {"1100","1100","0000","0000"},
      |                         ^~~~~~
a.cc:8:32: error: initializer-string for 'char [4]' is too long [-fpermissive]
    8 |                 {"1100","1100","0000","0000"},
      |                                ^~~~~~
a.cc:8:39: error: initializer-string for 'char [4]' is too long [-fpermissive]
    8 |                 {"1100","1100","0000","0000"},
      |                                       ^~~~~~
a.cc:9:18: error: initializer-string for 'char [4]' is too long [-fpermissive]
    9 |                 {"1000","1000","1000","1000"},
      |                  ^~~~~~
a.cc:9:25: error: initializer-string for 'char [4]' is too long [-fpermissive]
    9 |                 {"1000","1000","1000","1000"},
      |                         ^~~~~~
a.cc:9:32: error: initializer-string for 'char [4]' is too long [-fpermissive]
    9 |                 {"1000","1000","1000","1000"},
      |                                ^~~~~~
a.cc:9:39: error: initializer-string for 'char [4]' is too long [-fpermissive]
    9 |                 {"1000","1000","1000","1000"},
      |                                       ^~~~~~
a.cc:10:18: error: initializer-string for 'char [4]' is too long [-fpermissive]
   10 |                 {"1111","0000","0000","0000"},
      |                  ^~~~~~
a.cc:10:25: error: initializer-string for 'char [4]' is too long [-fpermissive]
   10 |                 {"1111","0000","0000","0000"},
      |                         ^~~~~~
a.cc:10:32: error: initializer-string for 'char [4]' is too long [-fpermissive]
   10 |                 {"1111","0000","0000","0000"},
      |                                ^~~~~~
a.cc:10:39: error: initializer-string for 'char [4]' is too long [-fpermissive]
   10 |                 {"1111","0000","0000","0000"},
      |                                       ^~~~~~
a.cc:11:18: error: initializer-string for 'char [4]' is too long [-fpermissive]
   11 |                 {"0100","1100","1000","0000"},
      |                  ^~~~~~
a.cc:11:25: error: initializer-string for 'char [4]' is too long [-fpermissive]
   11 |                 {"0100","1100","1000","0000"},
      |                         ^~~~~~
a.cc:11:32: error: initializer-string for 'char [4]' is too long [-fpermissive]
   11 |                 {"0100","1100","1000","0000"},
      |                                ^~~~~~
a.cc:11:39: error: initializer-string for 'char [4]' is too long [-fpermissive]
   11 |                 {"0100","1100","1000","0000"},
      |                                       ^~~~~~
a.cc:12:18: error: initializer-string for 'char [4]' is too long [-fpermissive]
   12 |                 {"1100","0110","0000","0000"},
      |                  ^~~~~~
a.cc:12:25: error: initializer-string for 'char [4]' is too long [-fpermissive]
   12 |                 {"1100","0110","0000","0000"},
      |                         ^~~~~~
a.cc:12:32: error: initializer-string for 'char [4]' is too long [-fpermissive]
   12 |                 {"1100","0110","0000","0000"},
      |                                ^~~~~~
a.cc:12:39: error: initializer-string for 'char [4]' is too long [-fpermissive]
   12 |                 {"1100","0110","0000","0000"},
      |                                       ^~~~~~
a.cc:13:18: error: initializer-string for 'char [4]' is too long [-fpermissive]
   13 |                 {"1000","1100","0100","0000"},
      |                  ^~~~~~
a.cc:13:25: error: initializer-string for 'char [4]' is too long [-fpermissive]
   13 |                 {"1000","1100","0100","0000"},
      |                         ^~~~~~
a.cc:13:32: error: initializer-string for 'char [4]' is too long [-fpermissive]
   13 |                 {"1000","1100","0100","0000"},
      |                                ^~~~~~
a.cc:13:39: error: initializer-string for 'char [4]' is too long [-fpermissive]
   13 |                 {"1000","1100","0100","0000"},
      |                                       ^~~~~~
a.cc:14:18: error: initializer-string for 'char [4]' is too long [-fpermissive]
   14 |                 {"0110","1100","0000","0000"}
      |                  ^~~~~~
a.cc:14:25: error: initializer-string for 'char [4]' is too long [-fpermissive]
   14 |                 {"0110","1100","0000","0000"}
      |                         ^~~~~~
a.cc:14:32: error: initializer-string for 'char [4]' is too long [-fpermissive]
   14 |                 {"0110","1100","0000","0000"}
      |                                ^~~~~~
a.cc:14:39: error: initializer-string for 'char [4]' is too long [-fpermissive]
   14 |                 {"0110","1100","0000","0000"}
      |                                       ^~~~~~