How to separate digits from a number in C++?

Question

I'm trying to find a way to get 5 digits separately from a whole number.

cin >> option;      // Option to enter a number(don't worry about this)
if (option == 1)    // The option(don't worry)
{
    cout << " enter 5 digit key 0 to 9 \n";
    readin(key);    // The input number that needs the digits to be separated
}

The code above just inputs the number, but I want to separate the digits somehow...But how?

Here's a hint - look into the [`%` (modulo) operator](http://en.wikipedia.org/wiki/Modulo_operator). — wkl, Dec 01 '11 at 02:42

SundayMonday · Accepted Answer · 2011-12-01T17:23:23.913

4

something like this:

// handle negative values
key = ABS(key);

while(key > 0)
{
    // get the digit in the one's place (example: 12345 % 10 is 5)
    int digit = key % 10;

    // remove the digit in the one's place
    key /= 10;
}

edited Dec 01 '11 at 17:23

answered Dec 01 '11 at 02:43

SundayMonday

19,147
29
100
154

1

+1. You could also add a quick check before the loop for negative numbers. If the number is negative, output or store the `-` and then `key = -key;` to make it positive before entering the loop. – Chris Parton Dec 01 '11 at 03:23

score 2 · Answer 2 · answered Dec 01 '11 at 03:15

2

Why not read each input individually and handle them individually?

i.e.

cout<< " enter 5 digit key 0 to 9 \n";
char str[5];
cin.get(str, 5);

for (int i = 0; i < 5; ++i)
{
    //do something with str[i];
}

answered Dec 01 '11 at 03:15

agenttom

163
1
6

+1, and "do something" might well start with `str[i] -= '0';`. – Steve Jessop Dec 01 '11 at 03:16

Taha · Answer 3 · 2011-12-02T19:05:06.930

1

You may use the following code snippet, it will separate the digits in reverse order inwhile loop.

int i;
cin >> i;

while (i%10 != 0) 
{
  cout << i%10 << endl;
  i = i/10;
}

edited Dec 02 '11 at 19:05

answered Dec 01 '11 at 08:04

Taha

1,086
1
10
20

score 0 · Answer 4 · edited Dec 14 '13 at 15:04

0

The while loop method will only take care of digits without zeroes.

edited Dec 14 '13 at 15:04

Undo

25,519
37
106
129

answered Dec 14 '13 at 14:33

Peterlo

1

score 0 · Answer 5 · answered Dec 14 '13 at 14:51

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

int main()
{
  string str;
  cin >> str;

  size_t len = str.size();
  len = len > 5 ? 5 : len;

  for (size_t i=0; i<len; ++i)
  {
    cout << "digit " << i << " is: " << (str[i] - '0') << endl;
  }

  return 0;
}

I do it in this way

How to separate digits from a number in C++?

5 Answers5