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egolovin

Oct 10th, 2008 8:55 pm

binary to decimal

can someone look at this? in theory it should work but i cant figure it out
thanks in advance

#include<iostream>

#include<string>

#include<cmath>

using namespace std;

void binToDec(string getBinary);

int main()

{

        string getBinary;

        cout<<"Enter a Binary Number:"<<endl;

        cin>>getBinary;

        binToDec(getBinary);

        

return 0;

}

void binToDec(string getBinary)

{

        int setLength,total=0;

        double placeholder=0;

        setLength=getBinary.size();

        

        for(int i=setLength;i>0;i--)

        {

                int num=pow(2.0,placeholder);

                int test=getBinary[i];

                if (test==1)

                {

                        total=total+num;

                }



                placeholder=placeholder +1;

        

        }

        cout<<total<<endl;





}

Rhohitman

Oct 10th, 2008 9:06 pm

Re: binary to decimal

I guess using string is not the good idea.
What we use to do was.... some how take the binary in the int or long.

then take a loop and extract the element one by one form the last...

I guess this is the efficient method.. some how you are wasting too much memory space using string.

int dec;

int bin;

cin>>bin;



for(int i=0; bin!=0; bin/=10)

  dec+=bin%10*pow(2, i++);

egolovin

Oct 10th, 2008 9:12 pm

Re: binary to decimal

oh sorry i forgot to add i have to use string as binary this is hw for school. pow only works with double. :(

Rhohitman

Oct 10th, 2008 9:20 pm

Re: binary to decimal

Quote:

Originally Posted by egolovin (Post 709904)

oh sorry i forgot to add i have to use string as binary this is hw for school. pow only works with double. :(

if you are such crazy about the string.
then you must subtract 48 from the each character of the string

as ASCII value of 1 is 49
when you subtract 49-48 = 1
then you can use it as normally

dougy83

Oct 10th, 2008 10:52 pm

Re: binary to decimal

What

Quote:

Originally Posted by egolovin (Post 709894)

can someone look at this? in theory it should work but i cant figure it out
thanks in advance

        if (test==1)

That line should be

           if (test == '1')

1 is different to '1' (character code 49, as Rhohitman said). Also, for powers of 2 you don't have to use pow(). Using the shift operator<< works fine for integers. So

pow(2., x)

can be replaced with

1<<x

egolovin

Oct 11th, 2008 8:53 am

Re: binary to decimal

Thanks alot :d

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