如何使用算法将十进制数转换为二进制数

Question

We were given this question in class to go and write an algorithm for converting a decimal number to binary number and tomorrow present it, I myself had tried the question.

1. start
2. i=0, count=0
3. if i<=n goto step 4
4. r=n%2
5. n=n/2
6. count= count+1
7. store remainder
8. if count=9 true print number
9. else goto step 3
10. end

Answer 1

If you want a more STL-ish and C++-ish solution, I suggest you using std::bitset (introduced in C++11) which represents a fixed-size sequence of N bits.

#include <bitset>
#include <string>
#include <climits>
#include <iostream>

std::string int_to_binary(int const value) {
    std::bitset<sizeof(int) * CHAR_BIT> bs(value);
    return bs.to_string();
}

int main() {
    std::cout << int_to_binary(1) << std::endl;
    std::cout << int_to_binary(2) << std::endl;
    std::cout << int_to_binary(3) << std::endl;

    return 0;
}

Check it out live .

Furthermore, if you want to make your int_to_binary function a bit more generic, you could turn it into a template function and take some time and research about SFINAE and std::enable_if . Here is how your function now could look like:

template <typename T,
          typename std::enable_if<std::is_integral<T>::value>::type* = nullptr>
std::string int_to_binary(T const value) {
    std::bitset<sizeof(T) * CHAR_BIT> bs(value);
    return bs.to_string();
}