two strings sum in another string

[Victor89]

My program works something like this:
First string: 123
Second string :321
123 + 321 = 444
----------------------------------------
I want to make it like this:
First string: 1 2 3
Second string: 3 2 1
1 2 3 + 3 2 1 = 4 4 4

#include <iostream>
#include <string.h>
#include <conio.h>
using namespace std;

int main()
{
	char a[10], b[10], c[20];
	int sum, n1, n2;
	
	cout << "First string of integers: ";
	cin.getline(a,10);
	
	cout << "Second string of integers: ";
	cin.getline(b,10);

	n1 = atoi(a);
	n2 = atoi(b);
	sum = atoi(a) + atoi(b);

    cout << a << "+" << b << "=" << sum;

	_getch();
}

[jlb]

Why are you storing these numbers in C-strings? Why not just get the information from the user as integers?

Since this is C++ why the C-strings instead of std::string, and then stringstreams instead of atoi()?

[Victor89]

I can solve this problem very easy using arrays.
But I found this problem in a c++ book, and I want to practice strings.