Simple Bit Manipulation Program

Sample of what output is supposed to look like:
http://img156.imageshack.us/my.php?image=scan1pp0.gif

Basically, I'm supposed to write a program to continually take a set of inputted binary numbers, while displaying the inputted sums in decimal, hex and binary.

Here is a flowchart of how the program is supposed to be done:
http://img165.imageshack.us/my.php?image=scan2ib8.gif

I'm having trouble getting the inputted numbers (which are characters) to be placed into a variable as a real number.

So far this is what I have:

Code:

---

#include "stdafx.h"
#include "stdio.h"

int main(int argc, char* argv[]) {

    unsigned char c, b, n;
    int sum, done;
    sum=0;
    done=0;
    int i=8;

    n=0;
    printf("Enter a binary number:");
    c=getchar();

    if (c=='q'||c=='Q') {
        getchar();
        return 0;
    } else {
        for ( int x = 0; x < 8; x++ ) {
            b=c&1;
            n=n<<1;
            n=b|1;
        }
        sum=sum+n;
       
        printf("sum = &#37;d decimal %x hex and " , sum, sum);
    }

    getchar();
    return 0;
}

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In the second .gif I linked to, it states that after I get the inputted characters into c, I'm supposed to make b= LSB(Least significant bit) of 'c' and then Shift 'n' left 1 bit and insert 'b' into 'n' as the new LSB

I just don't understand how to write the code so that it would continually scan until it has all of the inputted numbers into a variable as a real set of bits.

I thank you for your time and any advice anyone can give.

This:

Code:

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for(;;);

---

Is an infinite loop with no way to get out of it. You don't want to be doing that.

It would probably be easiest to read in the binary characters as a string using fgets(), then looping through each character in your string checking if its zero or not.

I'm not allowed to use commands I haven't been taught yet :(
The Professor wants me to do it only by bit manipulation, getchar and putchar.

Code:

---

#include "stdafx.h"
#include "stdio.h"

int main(int argc, char* argv[]) {

    unsigned char c, b, n;
    int sum, done;
    sum=0;
    done=0;
    int i=8;

    n=0;
    printf("Enter a binary number:");
    c=getchar();

    if (c=='q'||c=='Q') {
        getchar();
        return 0;
    } else {
        for ( int x = 0; x < 8; x++ ) {
            b=c&1;
            n=n<<1;
            n=b|1;
        }
        sum=sum+n;
       
        printf("sum = &#37;d decimal %x hex and " , sum, sum);
    }

    getchar();
    return 0;
}

---

Formated your code so I could read it, then, changed the for(;;); to getchar();. Your intent with the for(;;);s was to pause the program right? Well pausing for user input is a lot healthier of a way of doing that, and since you are allowed to use getchar(), why not ! :D

As to your input issues, you are only reading one character, and assuming you follow what your program told you to do, you will get either a '0' or a '1' (which, btw are the ascii symbols 0 and 1, the value stored in the char isn't actually the number 0 or 1) If you want to read more characters, you are going to have to loop, that is, if you have to use getchar().

Quote:

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As to your input issues, you are only reading one character, and assuming you follow what your program told you to do, you will get either a '0' or a '1' (which, btw are the ascii symbols 0 and 1, the value stored in the char isn't actually the number 0 or 1) If you want to read more characters, you are going to have to loop, that is, if you have to use getchar().

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EDIT:
I appreciate the tips/help. How would I write the loop so that it would only require the user to input 1 set of numbers? I'm not sure how that would work if I would only use getchar() which only stores a single character.

If I insert those scanned characters into a variable that is declared as an integer, would it then count as the actual numbers of 1 and 0?

Thanks again.

Perhaps do the input and calculations within your loop. Something like:

Code:

---

for(int x = 0; x< 8; x++)
{
    c=getchar();
    c-='0';
    n=n<<1;
    n=c|1;
}

---

With that example any non zero character would be counted as a 1 so you might want to add some validation too.

[edit] BTW declaring an int in your for loop C++ only, not valid C [/edit]

Quote:

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Originally Posted by mike_g

Code:

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for(int x = 0; x< 8; x++)
{
    c=getchar();
    c-='0';
    n=n<<1;
    n=c|1;
}

---

---

To Soosha: The blue code above doesn't look right to me. What is is supposed to do? [I know what it DOES, but that's probably not what you actually wanted... ]

You may also want to CHECK that the input is valid - e.g. '0' or '1' - otherwise the above "math" will produce "interesting" results.

--
Mats

Oh yeah >_< you want to be 'anding', not 'oring' there.

Quote:

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Originally Posted by mike_g

Oh yeah >_< you want to be 'anding', not 'oring' there.

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Not sure about that - but I'm sure we can agree that the "current" code is broken. [Actually, there is an argument for using and, but if we go that route, we could actually remove another statement - I'll leave it to others to figure out which].

Since this is almost certainly a "homework" question, I'm reluctant to provide specific code.

--
Mats