Binary to decimal progam

[Morgan Huguelet]

Hello im writng a program that converts binary to decimals. i feel like im doing this all wrong considering its not working right.any help would be great!

//this program converts Binary numbers to decimals
#include <iostream.h>

main()

{
      int a , b, c, d, e, f, g, dec;
   cout << "Enter a 7 bit binary value you wish to convert into decimal: " << '\n'; // asks user for binary
   cin >> a,b,c,d,e,f,g; 
   
g = g * 1;
cout << g;
f = f * 2;
e = e * 4;
d = d * 8;
c = c * 16;
b = b * 32;
a = a * 64;
dec = a + b + c + d + e + f + g;

cout << " Your decimal is:" << dec << '/n'; 
   
    system("pause");
   return 0;
}

[codekiddy]

http://www.parashift.com/c++-faq-lite/input-output.html#faq-15.13

[15.13] How can I "reopen" std::cin and std::cout in binary mode?

This is implementation dependent. Check with your compiler's documentation.

For example, suppose you want to do binary I/O using std::cin and std::cout.

Unfortunately there is no standard way to cause std::cin, std::cout, and/or std::cerr to be opened in binary mode. Closing the streams and attempting to reopen them in binary mode might have unexpected or undesirable results.

On systems where it makes a difference, the implementation might provide a way to make them binary streams, but you would have to check the implementation specifics to find out.

[naraku9333]

This shouldn't compile let alone work. You're taking input wrong, insert to each variable separately or parse the digits using division and modulus.

[o1vk4iN6]

There would be a problem with "dec", since that is used by std, unless you aren't using the entire namespace it'll be fine.

You can even do something more like this:

const int bits = 7;
int value = 0;

cout << "Enter a " << bits << " bit binary value: ";

for(int i = 1; i <= bits; i++)
{
    char c;
    cin >> c;
 
    if(c == '1')
         value |= 1 << (bits - i);
}

cout << "Decimal is: " << value << endl;

That'll only work for as long as "value" has enough memory to store all the bits, so up to 32 in this case.