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decimal to octal on C++

Discussion in 'C++' started by compscichick, Sep 7, 2010.

  1. compscichick

    compscichick New Member

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    The questions is: obtain the number of divisions performed (converting decimal to octal) to get the octal form.

    I have a c++ program that already does decimal to octal, but idk how to show how many divisions (or times the program goes through the algorithm). Any help?
     
  2. LordN3mrod

    LordN3mrod New Member

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    easiest way - store a global variable, say numOfDiv. Every time you perform a division, increment the variable. That's all :)
     
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  3. compscichick

    compscichick New Member

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    could you give an example...it doesn't have to pertain to my solution, its just been over a year since I have been programming and I cant find anything on google search
     
  4. LordN3mrod

    LordN3mrod New Member

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    OK, I'll write a program that does, ermm... say, prime-factorization

    Code:
    #include <iostream>
    int main()
    {
         using namespace std;
         int n;
         cin >> n;
         cout << n << " = 1" ;
         for(int i = 2; i * i <=n ;++i)
         {
             while(n%i == 0)
             {
                 cout  << " * " << i;
                 n /= i; //n = n/i
             }
         }
         if(n > 1)
            cout <<" * " << n;
        cout << endl;
        cin.get();
    }
    
    So, if you wanna know how many times operator / was called do it like this

    Code:
    #include <iostream>
    int divCount = 0;
    int main()
    {
         using namespace std;
         int n;
         cin >> n;
         cout << n << " = 1" ;
         for(int i = 2; i * i <=n ;++i)
         {
             while(n%i == 0)
             {
                 cout  << " * " << i;
                 n /= i;// DIVISION HERE!!! INCREMENT DIVCOUNT
                ++divCount;
             }
         }
         if(n > 1)
            cout <<" * " << n;
        cout << endl << divCount << endl;
        cin.get();
    }
    
    You may rightfully think that % is also division, and you might wanna count them too. Like this

    Code:
    #include <iostream>
    int divCount = 0;
    int main()
    {
         using namespace std;
         int n;
         cin >> n;
         cout << n << " = 1" ;
         for(int i = 2; i * i <=n ;++i)
         {
             int rem = n%i; //DIVISION HERE INCREMENT divCount;
             ++divCount;
             while(rem == 0)
             {
                 cout  << " * " << i;
                 n /= i;// DIVISION HERE!!! INCREMENT DIVCOUNT
                ++divCount;
                rem = n%i; //DIVISION HERE INCREMENT divCount;
               ++divCount;
             }
         }
         if(n > 1)
            cout <<" * " << n;
        cout << endl <<divCount << endl;
        cin.get();
    }
    
    Hope this helped
    Best Regards
     
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  5. compscichick

    compscichick New Member

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    Code:
    #include <iostream>
    using namespace std;
    int numOfDiv;
    
    void dec2oct(int n) {
    	
    	int leastSig=0;
    	int mostSig=0;
    
    	leastSig=n%8;
    	++numOfDiv;
    	mostSig=n/8;
    	++numOfDiv;
    	if(mostSig>7){
    		dec2oct(mostSig);
    	}
    	else{
    		cout<<mostSig;
    	}
    
    	cout<<leastSig;
    	
    }
    
    int main(){
    	int num = 35;
    	cout<< numOfDiv << endl;
    	cout << oct << num << endl;
    	cout << dec;
    	dec2oct(num);
    	int x;
    	cin>>x;
    	return 0;
    
    }
    
    
    
    it never counts, I just get a return output of 0. Is there something I am missing?
     
  6. shabbir

    shabbir Administrator Staff Member

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    You are outputting that variable before increment and then the program ends. Variables do not have persistency i.e. store values across runs.
     
  7. LordN3mrod

    LordN3mrod New Member

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    instead of the final int x; cin >> x; write just
    Code:
    cin.get();
    
    Also, move the line
    Code:
    cout<< numOfDiv << endl;
    
    after the line
    Code:
    dec2oct(num);
    
    And everything will be fine :)
     
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