[browngod2002]

I am trying to convert a binary number input by a user into a decimal number. I know how to so it on paper but getting C to do it I am lost. I am using Dev-C compiler. Here is what I got so far.

#include<stdio.h>
		  #include<math.h>
		  #include<string.h>

int bin2dec(int decimal);

int main(void)
{
	int num;

	printf("The decimal equilavent is: %d", bin2dec(decimal));

getchar();
getchar();
return 0;
}

int bin2dec(int decimal)
{
	int num[10];
	int i;
	int bin;
	int arr1[10];
	int arr2[10] = {512,256,128,64,32,16,8,4,2,1};

	printf("Enter a binary(0's and 1's) number: ");
	scanf("%d", &arr1);

This is qheere I get confused.
for (i = 0; i < arr1; i++)
{
	if (arr1[i] == 1)
		num[i] = arr1[i];
		arr2[i]= num[i]
		decimal = arr2[i];
}

return decimal;
}

[Israel]

Ok, I'm not even going to pretend to know how to answer your question. I know a little C++ but I think your beyond me here. But if I were you I might view a web page like this which does the same thing with javascript and maybe look at how some of the functions they used worked. I know don't know if this will help you but good luck.

[dorknexus]

the following snippet contains functions which convert alpha-numeric values (which are decimal representations of letters) into binary. and towards the bottom of that snippet post, there are functions which convert binary back into the decimal values.

http://code.dreaminc...t/snippet30.htm

be aware that this takes binary in the form of right-to-left, meaning that the decimal value 2 is represented as 01.

whereas the left-to-right form would represent 2 as 10

[born2c0de]

Always use the Bitwise AND Operator for such conversions.

int i, ch;
printf("Enter an integer: ");
scanf("%c",&ch);
for(i=0x80; i;i=i>>1)
 printf("%d", ( (ch&i) ? 1 : 0 ) );

You can also use the itoa function to do this.

/*
i is the number to be converted
c is the buffer (char[]) where the binary number is stored.
2 represents the base which the source (ie. i ) has to be converted into.
*/
itoa(i,c,2);
printf("%s",c);

If you can see something in the Previous code that used the For loop, you will see the possibility of using a recursive function to do this.

[browngod2002]

Thank you born2c0de that was helpful
I am new so somethings seems difficult than they are.

This post has been edited by Dark_Nexus: 25 September 2006 - 08:46 AM

[browngod2002]

I am trying to convert bin to dec without putting it into an array or a string here is the code I have so far. I need someone to tell me why it is not working. I am using VC++ 2005 Express Edition.

#include "stdafx.h"
#include <stdio.h>
#include<math.h>

int bin2dec(int decimal);



int main()
{
	int decimal;

	printf("Enter an integer: ");
	scanf_s("%c",&decimal);
	
	
	 printf("The decimal equivalent = %d\n",bin2dec(decimal));
		
getchar();
getchar();
return 0;
}

int bin2dec(int decimal)
{
	int total = 0;
	int power = 1;

	while(decimal > 0)
	{
		total += decimal % 10 *power;
		decimal = decimal / 10;
		power = power * 2;
	}
	
	return decimal;
}

This post has been edited by browngod2002: 25 September 2006 - 05:15 PM

[Jayman]

I believe the problem lies here scanf_s("%c",&decimal); (although I did not put this in a compiler to check it). Your variable decimal is of type integer, but you are using the character format specifier. Change your format specifer to match your variable type.

scanf_s("%d",&decimal);

It would be of great benefit if you describe in what way your application is not working, so that someone can better help you.

List error messages, incorrect output, compilation errors.

[Vagabond]

This is a small program I wrote some time ago I don't know if the concepts will help.

 
 
snippet......		 

switch(choise)
{
	case 1: cout << "Enter a Hex number: ";
				 cin  >> hex >> number;
			cout << "\n   value in octal = "
				   << oct << number << endl;
			cout << " value in decimal = "
				   << dec << number << endl;
		 break;
	case 2: cout << "Enter a Octal number: ";
			 cin  >> oct >> number;
			cout << "\n	   value in hex = "
			   << hex << number << endl;
			cout << "   value in decimal = "
			   << dec << number << endl;
		break;
	case 3: cout << "Enter a dec number: ";
			 cin  >> dec >> number;
			cout << "\n   value in octal = "
			   << oct << number << endl;
			cout << "	 value in hex = "
			   << hex << number << endl;
		break;
	case 4:  cout << "Program terminated by user...";
			 exit(0);
	default : cout << "ERROR ~ Invalid selection\n\n";
		 break;
}

If there arn't any objections I can put the compelted code up if you wish.

This post has been edited by Vagabond: 26 September 2006 - 03:17 AM

[browngod2002]

When I build and run the program I get no errors or warnings but the output is all wrong. I think it is in my formula but I can't get the formula to work right.Here is the updated code.

#include "stdafx.h"
#include <stdio.h>
#include <math.h>

/* function prototype */
int bintodec(int decimal);


int _tmain(int argc, _TCHAR* argv[])
{
	int decimal;

	printf("Enter an interger (0's and 1's): ");
	scanf_s("%d", &decimal);

	printf("The decimal equilavent is %d.\n", bintodec(decimal));

	getchar();
	getchar();
	return 0;
}

int bintodec(int decimal)
{
	int total = 0;
	int power = 1;
	int number = 0;

	decimal--;
	while(decimal >=0)
	{
					   /* this is where the problem is I need some advice on how to fix it.*/
					  
		total += decimal % 10 * power;
		decimal = decimal / 10;
		power = power * 2;
		number += decimal;
		decimal--;
	}

	return number;
}

This post has been edited by Dark_Nexus: 26 September 2006 - 09:54 PM

[Jayman]

Maybe the following link will help explain how to convert.

http://www.is.wayne....inary/page3.htm

[browngod2002]

Thank all of you that helped me figure this problem out. I was returning the wrong value in my function(returning decimal instead of total). Here is my finished code and I have also posted it in the code snippets page for future user that may have the same problem that i did.

#include "stdafx.h"
#include <stdio.h>
#include <math.h>

/* function prototype */
int bintodec(int decimal);


int _tmain(int argc, _TCHAR* argv[])
{
	int decimal;

	printf("Enter an interger (0's and 1's): ");
	scanf_s("%d", &decimal);

	printf("The decimal equilavent is %d.\n", bintodec(decimal));

	getchar();
	getchar();
	return 0;
}

int bintodec(int decimal)
{
	int total = 0;
	int power = 1;
	

	
	while(decimal > 0)
	{
		total += decimal % 10 * power;
		decimal = decimal / 10;
		power = power * 2;
		}

	return total;
}

This post has been edited by browngod2002: 26 September 2006 - 03:52 PM

[boelegg52]

Thanks everybody for the information on converting binary to decimal

[CTphpnwb]

Belated, but here's a more generic method I wrote.

#include <iostream>
#include <math.h>
using namespace std;
int bin, decimal = 12, decimal2;
int base_one = 10, base_two = 2;
int convert(int num, int starting_base, int destination_base);
int main (int argc, char * const argv[]) {
	bin = convert(decimal, base_one, base_two);
	cout << "Base"<< base_one<< " "<< decimal << " = Base"<< base_two<< " " << bin << endl;
	decimal2 = convert(bin, base_two, base_one);
	cout << "Base"<< base_two << " " << bin << " = Base"<< base_one << " " << decimal2 << endl;
	return 0;
}
int convert(int num, int starting_base, int destination_base)
{
	int val = 0, count = 0;
	while (num) {
		val += pow(starting_base, count) * (num % destination_base);
		count++;
		num /= destination_base;
	}
	return val;
}