added fen notation

fen.c

+#include<stdio.h>
+
+int side;
+void fen(char *my_fen){
+	// first reset the board
+	reset();
+	
+	for(int i = 0 ; i<8 ; i++){		//loop over the ranks
+		for(int j=0;j<16;j++ ){		// loop over the files
+			
+			int square = 16 * i + j; 
+			
+			// first part of fen 
+			if(!(square & 0x88)){
+				if((*my_fen >= 'a' && *my_fen <= 'z')|| (*my_fen >= 'A' && *my_fen <= 'Z') ){
+					board[square] = char_pieces[*my_fen];
+					*my_fen++;
+
+				}
+				if(*my_fen >= '0' && *my_fen <= '8'){
+					j += *my_fen-'0';
+					*my_fen++;
+				}
+				if(*my_fen=='/'){
+					*my_fen++;
+				
+				}
+			}
+					
+		}
+			
+	}
+	*my_fen++;
+	// second part of FEN
+	if(*my_fen == 'w'){
+		side = white;
+	
+	}
+	else{
+		side = black;
+	}
+	show_board();
+	
+	
+	// castling 
+	// en passant
+	
+	
+}