hello guys,

i have written a simple program in c++ to convert a byte to binary number but i do not understand what the complier is try to tell me. the program and error are below.if any one can understand them please mail me. Cheers!!

====================
C++ Program (cnvt.cc)
====================
#include <iostream>

void binary_op(char byte);

int main()
{
char byte=55;
binary_op(byte);
return 0;
}

void binary_op(char byte)
{
int count =8;
while(count--)
{
printf("%d",(byte&128) ? 1 : 0);
byte<<=1;
}
printf("\n");
}

here is the error when i have tried to compiled the program
the commad i used and the errors are showen below

suman@linux:~> gcc cnvt.cc
======
errors
======
/tmp/cc1RdLHm.o(.text+0xa0): In function `__static_initialization_and_destruction_0(int, int)':
: undefined reference to `std::ios_base::Init::Init[in-charge]()'
/tmp/cc1RdLHm.o(.text+0xcf): In function `__tcf_0':
: undefined reference to `std::ios_base::Init::~Init [in-charge]()'
/tmp/cc1RdLHm.o(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status

ok, you need to choose if your using c or c++.

to make it c replace '#include <iostream>' with '#include <stdio.h>' and rename to cnvt.c

to make it c++ replace '#include <iostream>' with '#include <cstdio>' add the line 'using namespace std;' after the #include and compile with g++ not gcc

thank you for your suggestion. i made the changes and it worked.

it looks like the new GCC has quite a lot of changes added to it. Could you tell me if there is a data type for stroing binary numbers in GCC.

Numbers are infact stored binary in memory , by the way if you want to do some bit manipulations <<, >>, |, &, and ^ operators are useful.

well all (signed integer)numbers are stored in two's complement binary notation so any of int, char, long, etc store the numbers in binary. if your actual question is - is there a function to convert a number to a base2(binary) string then there is, its called itoa but unfortunatly its not ansi c, i dont know if gcc supports it or not. its better to write your own version of itoa as its not very hard to do.

The other way is to change your number into string (using itoa(), which is an ANSI C function, or sprintf()) and then strtoul() or strtol().
But that's too dirty. The best way is to use bitwise operators.

hi mohsen
i do not think those function will work in GCC. but i will try them out. i think the best option will be to a customised function than relying on the inbuild ones.

yes, btw those mentioned functions are ANSI and present in GCC (stdio and stdlib I think)

itoa is not ANSI C, check this under portability, and according to a grep of my /usr/include its not in my glibc

oh yes I mixed that with atoi