Converting decimal to binary & printing binary in a for loop?

I'm learning C right now %26amp; I have to covert decimal to binary. And I'm having issues printing 8 bits of binary. I know how to convert decimal to binary by hand, but I don't understand what I am doing wrong in my program. How can I print 8 bits of binary in a for loop?





MY CODE:


===============================


#include %26lt;stdio.h%26gt;





void main()


{


//declare %26amp; initialize variables


int dec = 0; //decimal number


int dect = 0; //test the decimal


int i; //counter


int bitAmount = 3; //amount of bits to shift





//prompt user to enter int


printf("Enter a integer: ");


scanf("%d", %26amp;dec);





//convert the decimal into binary


for (i = 0; i %26lt; 8; i++) //print out 8 bits


{


//divide so you only get 0 or 1


if (dec != 0)


{


dec = dec % 2;





//extract the number


dec = dec / 2;


}


else


dec = 1;





//print the binary


printf("%d ", dec);





}





//pause screen


system("pause");


}





void dec2bin(int dec, char direction, int bitAmount)


{


int i; //counter





//convert the decimal to a binary


for (i = 0; i%26lt;=10, dec !=0; i*=10)


{


//divide to get only 0 %26amp; 1


dec = dec % 2;





//extract each number


dec = dec / 2;





//print each bit


printf("%d ", dec++);


}








}








what is wrong with my code???|||The first one you're clobbering "dec" without getting the bit value. If you're doing it like that where you use division, you MUST capture the value that you're losing when you divide, ie. that least significant bit. You could wrap an if statement around the assignment like this:


if ((dec /= 2) != 0) {


// print one


} else {


// print zero


}


or assign to a variable:


bit = (dec /= 2);


or do it twice:


bit = dec / 2; /* notice not writing back w/ /= operator */


dec /= 2; /* aka dec = dec / 2; */





You're also trying to print them backwards, that is, the least significant bit would get printed on the left instead of the right.





What you can do is shift out the bits to the left, and if the high bit is set, then print 1, otherwise print 0. That makes it easy to print it out in the correct direction, left -%26gt; right and most -%26gt; least significant bit.


for (i = 0; i %26lt; 8; i++) {


if ((dec %26amp; 0x80) != 0) {


printf("1");


} else {


printf("0");


}


dec %26lt;%26lt;= 1;


}





Or perhaps like this (exact same thing, different syntax:)


for (i = 0; i %26lt; 8; i++, dec %26lt;%26lt;= 1) {


printf("%d", (dec %26amp; 0x80) != 0));


}





Or you could do the printf this way too:


printf("%c", (dec %26amp; 0x80) ? '1' : '0');





Alternatively, you can shift a mask instead of the decimal value:


int mask;


for (mask = 0x80; mask %26gt; 0; mask /= 2) { /* or mask %26gt;%26gt;= 1, same thing as mask /= 2. */


printf("%d", ((mask %26amp; dec) != 0));


}