/*This prog supposed to convert from binary number system to decimal but
something is not
working properly please help*/

#include <iostream>
using namespace std;



int main()
{
	int a[8],sum=0;
	cout << endl;
	cout << "Input Binary number(with spaces between digits): ";
	for(int i=0;i<=7;i++)
	{

	   cin >> a[i];

	   if((a[i]!=1)&&(a[i]!=0))//Strange indeed!!! I tried || but my message
showed up.
	   {
	   cout << "You entered wrong digit!!!" << endl;
	   i--;
       }

   }



   for(int i=0;i<8;i++) // I also tried for(int i=7;i>=0;i--) but get same results
   {                    // results of 000000001 is 128 and of 10000000 is 1?!
	   if(a[i])
       {
	      switch(i)  // ofcourse I can just change cases but it is not the way
"for" must work...
	      {
		      case 0:
		      sum+=1;
		      break;
		      case 1:
		      sum += 2;
		      break;
		      case 2:
		      sum += 4;
		      break;
		      case 3:
		      sum += 8;
		      break;
		      case 4:
		      sum += 16;
		      break;
		      case 5:
		      sum += 32;
	          break;
	          case 6:
	          sum += 64;
	          break;
	          case 7:
	          sum += 128;
	          break;

	         default: cout << "This shall not happen!" << endl;
         }
        }
	 }

	 cout << sum;
}

Artur skrev:
> /*This prog supposed to convert from binary number system to decimal but
> something is not
> working properly please help*/


There is two things to notice.

First, when you enter the number you must have a space
or an enter between the numbers, otherwise it will see
it as one big numer.

Second, the program seems to handle the digits backwards,
if i enter 1 0 0 0 0 0 0 0, the answer is 1, whereas
get me 128.

try->

if((a[i]!=1)&(a[i]!=0))//

whit 1 &

Artur escreveu:
> /*This prog supposed to convert from binary number system to decimal but
> something is not
> working properly please help*/
> 
> #include <iostream>
> using namespace std;
> 
> 
> 
> int main()
> {
> 	int a[8],sum=0;
> 	cout << endl;
> 	cout << "Input Binary number(with spaces between digits): ";
> 	for(int i=0;i<=7;i++)
> 	{
> 
> 	   cin >> a[i];
> 
> 	   if((a[i]!=1)&&(a[i]!=0))//Strange indeed!!! I tried || but my message
> showed up.

Of course. Get a look on your reference material about the "short circuiting" property of the operators && and ||.

> 	   {
> 	   cout << "You entered wrong digit!!!" << endl;
> 	   i--;
>        }
> 
>    }
> 
> 
> 
>    for(int i=0;i<8;i++) // I also tried for(int i=7;i>=0;i--) but get same results
>    {                    // results of 000000001 is 128 and of 10000000 is 1?!

In order you can grok what's happening, try to print the digits in the loop. Will it make sense?