Binary to Decimal and Decimal to Binary converter

PROGRAM bindec;
USES crt;
VAR dec_begin, i: Integer;
bin_number: String;
zero_or_one, bin_or_dec: Char;
bin: String;
currHeading, intBinChar, x: Integer;
dec: Real;
repeat_char: Char;
BEGIN
	clrscr;
	REPEAT
		WRITELN('To convert binary to decimal, press B; to convert decimal to binary, press D');
		READLN(bin_or_dec);
		IF (bin_or_dec='D') OR (bin_or_dec='d') THEN
		BEGIN
		WRITELN('Please enter a decimal number to convert to binary: ');
			READLN(dec_begin);
			REPEAT
				IF (dec_begin mod 2) = 0 THEN zero_or_one := '0'
				ELSE zero_or_one := '1';
				bin_number := bin_number + zero_or_one;
				dec_begin := dec_begin div 2;
			UNTIL dec_begin = 0;
			FOR i := Length(bin_number) DOWNTO 1 DO
				WRITE(bin_number[i]);
		WRITELN;
		END
		ELSE
		BEGIN
			WRITELN('Please enter a binary number to convert to decimal: ');
			READLN(bin);
			dec := 0;
			currHeading := 0;
			FOR i := Length(bin) DOWNTO 0 DO
			BEGIN
				IF currHeading > 0 THEN currHeading := currHeading * 2
				ELSE currHeading := 1;
				Val(bin[i], intBinChar, x);
				dec := dec + (intBinChar * currHeading);
			END;
		WRITELN(dec:10:0);
		END;
		WRITELN('Repeat? Y/N');
		READLN(repeat_char);
	UNTIL (repeat_char = 'N') OR (repeat_char = 'n');
	READLN;
END.