brainfuck, 2120 bytes
Saved 1 byte thanks to Jo King.
+>,[>,[-<->]<[>>]>]<[<],]<.
Readable output! Readable output!
Takes input two characters at a time, and moves away from the 1 on the tape if any pair doesn't match. EOF is treated as 0 and thus handled automatically.
Output is a null byte if the string is not double speak, and 0x01 if it is. The readable version outputs these as characters at a cost of 14 bytes.
brainfuck, 21 bytes
+>,[>,[-<->]<[>>],]<.
Takes input two characters at a time, and moves away from the 1 on the tape if any pair doesn't match. EOF is treated as 0 and thus handled automatically.
Output is a null byte if the string is not double speak, and 0x01 if it is. The readable version outputs these as characters at a cost of 14 bytes.
brainfuck, 20 bytes
Saved 1 byte thanks to Jo King.
+>,[>,[-<->]<[<],]<.
Takes input two characters at a time, and moves away from the 1 on the tape if any pair doesn't match. EOF is treated as 0 and thus handled automatically.
Output is a null byte if the string is not double speak, and 0x01 if it is. The readable version outputs these as characters at a cost of 14 bytes.
brainfuck, 21 bytes
+>,[>,[-<->]<[>>],]<.
Takes input two characters at a time, and moves away from the 1 on the tape if any pair doesn't match. EOF is treated as 0 and thus handled automatically.
Output is a null byte if the string is not double speak, and 0x01 if it is. The readable version outputs these as characters at a cost of 14 bytes.