The file is in 0 and 1, but when you open it with text editor those bits are grouped in bytes and then treated as text ;) In Linux you could try to disassemble the output file to ensure that it contains machine instructions (x86 architecture):
objdump -D -mi386 a.out
Example output:
1: 83 ec 08 sub $0x8,%esp
4: be 01 00 00 00 mov $0x1,%esi
9: bf 00 00 00 00 mov $0x0,%edi
The second column contains that 0's and 1's in hexadecimal notation and the third column contains mnemonic assembler instructions.
If you want to display those 0's and 1's simply type:
xxd -b a.out
Example output:
0000000: 01111111 01000101 01001100 01000110 00000010 00000001 .ELF..
0000006: 00000001 00000000 00000000 00000000 00000000 00000000 ......