nkuebelbeck - 1 year ago 266
C++ Question

# Split an Integer into its digits c++

I'm trying to learn c++ on my own and I've hit a bit of a road block. The problem is I need to take an integer,split it into its digits and get the sum of the digits and display them.

Example:

input number:

`123456`

digits in the integer:
`1 2 3 4 5 6`

sum:
`21`

I have it all done, but when I rip the integer, into digits I can't display it correctly. It displays in reverse order.

So in the program below I enter
`1234`
and it spits out
`4 3 2 1`
. I know why, I just don't know how to fix it.

Here is my code so far:

``````#include "stdafx.h"
#include <cstdlib>
#include <iostream>
#include <math.h>

int countDigitsInInteger(int n)
{
int count =0;
while(n>0)
{
count++;
n=n/10;
}
return count;
}

using namespace std;

int main(int argc, char *argv[])
{
int intLength =0;
int number;
int digit;
int sum = 0;
string s;
cout << "Please enter an integer ";
cin >>number;
cout << "Orginal Number = "<<number <<endl;
//make the number positive
if (number<0)
number = -number;
intLength = countDigitsInInteger(number);
//break apart the integer into digits
while(number>0)
{
digit = number % 10;
number = number / 10;
cout <<digit << " ";
sum = sum+digit;
}
cout <<endl <<"Sum of the digits is: "<<sum<<endl;
system("PAUSE");
return EXIT_SUCCESS;
}
``````

Here is my solution

can't see :)

Your problem comes from the fact that you are reading the digits backwards, thus you need to print them out backwards. A stack will help you tremendously.

``````#include "stdafx.h"
#include <cstdlib>
#include <iostream>
#include <math.h>
#include <stack>

int countDigitsInInteger(int n)
{
int count =0;
while(n>0)
{
count++;
n=n/10;
}
return count;
}

using namespace std;

int main(int argc, char *argv[])
{
int intLength =0;
int number;
int digit;
int sum = 0;
string s;
cout << "Please enter an integer ";
cin >>number;
cout << "Orginal Number = "<<number <<endl;
//make the number positive
if (number<0)
number = -number;

intLength = countDigitsInInteger(number);
//break apart the integer into digits

stack<int> digitstack;
while(number>0)
{
digit = number % 10;
number = number / 10;
digitstack.push(digit);
sum = sum+digit;
}

while(digitstack.size() > 0)
{
cout << digitstack.top() << " ";
digitstack.pop();
}

cout <<endl <<"Sum of the digits is: "<<sum<<endl;
system("PAUSE");
return EXIT_SUCCESS;
}
``````

Oh, and BTW, keep your indentation clean. Its important.

EDIT: In response to Steve Townsend, this method is not necessarily overkill, it is just different from yours. The code can be slimmed down so that it seems less like overkill:

``````#include <iostream>
#include <stack>
#include <string>

using namespace std;

int getInput(string prompt)
{
int val;
cout << prompt;
cin >> val;
return val < 0 ? -val : val;
}

int main(int argc, char** argv)
{
int num = getInput("Enter a number: ");
cout << "Original Number: " << num << endl;

stack<int> digits;
int sum = 0;
while(num > 0)
{
digits.push(num % 10);
sum += digits.top();
num = num / 10;
}

while(digits.size() > 0)
{
cout << digits.top() << " ";
digits.pop();
}

cout << endl << "Sum of digits is " << sum << endl;

return 0;
}
``````
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