Is there a printf converter to print in binary format?

Question

I can print with printf as a hex or octal number. Is there a format tag to print as binary, or arbitrary base?

I am running gcc.

printf("%d %x %o\n", 10, 10, 10); //prints "10 A 12\n" print("%b\n", 10); // prints "%b\n" 

Answer 1

Hacky but works for me:

#define BYTE_TO_BINARY_PATTERN "%c%c%c%c%c%c%c%c" #define BYTE_TO_BINARY(byte)  \   (byte & 0x80 ? '1' : '0'), \   (byte & 0x40 ? '1' : '0'), \   (byte & 0x20 ? '1' : '0'), \   (byte & 0x10 ? '1' : '0'), \   (byte & 0x08 ? '1' : '0'), \   (byte & 0x04 ? '1' : '0'), \   (byte & 0x02 ? '1' : '0'), \   (byte & 0x01 ? '1' : '0')  

printf("Leading text "BYTE_TO_BINARY_PATTERN, BYTE_TO_BINARY(byte)); 

For multi-byte types

printf("m: "BYTE_TO_BINARY_PATTERN" "BYTE_TO_BINARY_PATTERN"\n",   BYTE_TO_BINARY(m>>8), BYTE_TO_BINARY(m)); 

You need all the extra quotes unfortunately. This approach has the efficiency risks of macros (don't pass a function as the argument to BYTE_TO_BINARY) but avoids the memory issues and multiple invocations of strcat in some of the other proposals here.