binary to decimal with function

[ft95]

hello,what is the problem in this program?

#include "stdafx.h"
#include<iostream>
#include<cmath>

using namespace std;
void BinarytoDecimal();
	int checkbinary(int );
	


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


void BinarytoDecimal()
{

const int arreysize=1000;
	int binarrey[arreysize];
	
	int number,sum;
	static int i=0;

	
	cout<<"Enter the binary number:";
	cin>>number;
	
	checkbinary(number);
	
	cout<<sum;
	

}

int checkbinary(int number)
{
int remain,i,counter;
double power,sum=0;
const int arreysize=1000;
	int binarrey[arreysize];


		for(i=0;number!=0;i++)
		{
		number=number/10;
		remain=number%10;
		
		if(remain>1)
		{
			cout<<"the number is wrong.please try again!";
			BinarytoDecimal();
			
		}
		else
			binarrey[i]=remain;
			
		}
		for(counter=0;counter<=i;counter++)
	{
		power=counter;
		sum=pow(2,power)*binarrey[counter]+sum;
		}
		return sum;

}

[Chervil]

At line 33 cout<<sum; the variable is output but it was never initialised, so the output is unpredictable.

At line 66 return sum; a value is returned from the function, but when the function is called on line 31 nothing is done with this result.

[ft95]

ok I know that. but whybut when the function is called on line 31 it does not do anything with this result.

[Chervil]

Lets say you want to find the square root of 25.

sqrt(25.0);
will do that.

But if you want to make use of the result you either need to display it directly
cout << sqrt(25.0);

or assign the result to a variable
double x = sqrt(25.0);


The same applies to the function you wrote yourself.

[ft95]

thank you so much...
I solved that problem but I think that this program has many problem yet.
thank you anyway

[ft95]

How can I get very long number in this program?
for example:0111100000000000011111111111101

// check 4.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include<iostream>
#include<cmath>

using namespace std;
void BinarytoDecimal();
	int checkbinary(int );
	


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









void BinarytoDecimal()
{

	
	long int number,sum;
	static int i=0;

	
	cout<<"Enter the binary number:";
	cin>>number;
	
	cout<<checkbinary(number);
	
	

}






int checkbinary(int number)
{
int remain,i,counter;
double power,sum=0;
const int arreysize=1000;
	int binarrey[arreysize];


		for(i=0;number!=0;i++)
		{
		remain=number%10;
		number=number/10;
	
		
		if(remain>1)
		{
			cout<<"the number is wrong.please try again!";
			BinarytoDecimal();
			
		}
		else
			binarrey[i]=remain;
			

		}
		for(counter=0;counter<i;counter++)
	{
		power=counter;
		sum=pow(2,power)*binarrey[counter]+sum;
		}
		return sum;

}




//*********************************************

[Stewbond]

I would make number a string instead of a long int.

[ft95]

ok,I didn't can use this.
can you explain more?
in checkbinary function it makes problem and I don't know what to do!!!!!!!!!!!

what aboat arrey?
What shoud I do if I want solve it with arrey?

[Stewbond]

#include <string>
#include <iostream>

int BinaryToDecimal(std::string& in)
{
	int decimal = 0;
	while (!in.empty())
	{
		decimal *= 2;
		if (in[0] == '1')
			decimal += 1;
			
		in.erase(in.begin());
	}
}

int main()
{
	std::string input;
	std::cout << "Input a binary number: ";
	std::cin >> input;
}

[ft95]

thank you so much...

[ft95]

If I just want to use arrey what shoud I do?(I shoudn't use string)
who knows?????

[ggarciabas]

You can get this example to know how to implement this with string:

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

using namespace std;

long int BinaryToDecimal (string binary)
{
	long int valor=0;
	int a;
	
	for (int i=0; i <= binary.size()-1; i++) {	
			a = binary[(binary.size()-1)-i];
			//cout << a-48 << endl;
			valor += pow(2, i) * (a-48); // -48, because the return is 1 on the ASCII table, and the first number 0 is 48
		}	
	
	return valor;
}

int main () {
	string binary;
	
	cout << "Inform binary: ";
	cin >> binary;
	
	cout << endl;
	cout << " Result : " << BinaryToDecimal(binary) << endl;

	return 0;
}

[ft95]

thank you.
but "without using string"!!!!!!!!!!!

[Volatile Pulse]

You need to specify since there are two styles of strings. You still need to use a string, but you want a C-String instead of a C++-String. The difference:

// C++ String
#include <string>

std::string myString = "Hello, World!";

// C String

char* myString[]= "Hello, World!";

For all intensive purposes, they're the same. If you need an array of C-Strings, you can do something like:

char* myStringArray[10][10]; // Allows 10 strings with a max length of 10 chars

// Reads 10 strings from the user
for (int i = 0; i < 10; i ++)
   std::cin >> myStringArray[i];

// Displays 10 strings
for (int i = 0; i < 10; i ++)
   std::cout << myStringArray[i] << "\n";