How do I split an int into its digits?

Question

How can I split an int in c++ to its single numbers? For example, I\'d like to split 23 to 2 and 3.

Answer 1

The following will do the trick

void splitNumber(std::list<int>& digits, int number) {
  if (0 == number) { 
    digits.push_back(0);
  } else {
    while (number != 0) {
      int last = number % 10;
      digits.push_front(last);
      number = (number - last) / 10;
    }
  }
}

Answer 2

int n = 1234;
std::string nstr = std::to_string(n);
std::cout << nstr[0]; // nstr[0] -> 1

I think this is the easiest way.

We need to use std::to_string() function to convert our int to string so it will automatically create the array with our digits. We can access them simply using index - nstr[0] will show 1;

Answer 3

Based on icecrime's answer I wrote this function

std::vector<int> intToDigits(int num_)
{
    std::vector<int> ret;
    string iStr = to_string(num_);

    for (int i = iStr.size() - 1; i >= 0; --i)
    {
        int units = pow(10, i);
        int digit = num_ / units % 10;
        ret.push_back(digit);
    }   

    return ret;
}

Answer 4

cast it to a string or char[] and loop on it

Answer 5

You can count how many digits you want to print first

#include <iostream>
#include <cmath>
using namespace std;

int main(){
int number, result, counter=0, zeros;

do{
    cout << "Introduce un numero entero: ";
  cin >> number;

  }while (number < 0);

  // We count how many digits we are going print
  for(int i = number; i > 0; i = i/10)
        counter++;

   while(number > 0){

       zeros = pow(10, counter - 1);

       result = number / zeros;
       number = number % zeros;
       counter--;

       //Muestra resultados
       cout << " " << result;
   }
   cout<<endl;

}

Answer 6

Start with the highest power of ten that fits into an int on your platform (for 32 bit int: 1.000.000.000) and perform an integer division by it. The result is the leftmost digit. Subtract this result multipled with the divisor from the original number, then continue the same game with the next lower power of ten and iterate until you reach 1.