Converting decimal to octal

Question

This is a simple program converting user input decimal numbers into octal ones.

#include <iostream>
using namespace std;
main()
{
    int de,oc,y,i=1,octal;
    float decimal,deci,x;
    cout<<"Enter decimal no :: ";
    cin>>decimal;
    de=decimal;
    deci=decimal-de;
    cout<<"("<<decimal<<")10 = (";
    while(de>0)
    {
        oc=de%8;
        de=de/8;
        octal=octal+(oc*i);
        i=i*10;
    }cout<<octal<<".";
    while(deci>0)
    {
        x=deci*8;
        y=x;
        deci=x-y;
        cout<<y;
    }
    cout<<")8";
}

Answer 1

Just, i don't understand why?

What's wrong with (for integer):

#include <iostream>
int main() {
    int input;
    std::cout << "Enter decimal number: ";
    std::cin >> std::dec >> input;
    std::cout << '\n' << std::oct << input << '\n';
}

And about your code:

• Avoid using namespace std, it's a bad practice
• Just main() isn't a valid prototype for the entry point, at least use `int main()
• Define variables in the closest scope possible.
• Try naming variable consistently
• de=de/8; can be simplified to de /= 8;
• floating point conversion is a bit more tricky than just doing what you do

Edit: After testing it (and correcting main() and) : Your code just doesn't work, even for an integer value

Enter decimal no :: (0)10 = (32767.)8
Enter decimal no :: (8)10 = (32776.)8
Enter decimal no :: (10)10 = (32779.)8

Test yourself