Question

How to convert an int into an array of ints in C++

Answer 1

#include <iostream>

#define LEN 5

void int_into_an_array_of_ints(int arr[], int n) {
    for (int i = LEN - 1; i >= 0; i--) {
        arr[i] = n % 10;
        n = n / 10;
    }
}

int main()
{
    int n = 78910;
    int arr[LEN];
    
    int_into_an_array_of_ints(arr, n);
 
    for (int i = 0; i < LEN; i++)
        std::cout << "arr[" << i << "] = " << arr[i] << "\n";
 
}


 
/*
run:
 
arr[0] = 7
arr[1] = 8
arr[2] = 9
arr[3] = 1
arr[4] = 0
 
*/

 

 

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Answer 2

#include <iostream>
#include <cmath>

void int_into_an_array_of_ints(int arr[], int n, int size) {
    for (int i = size - 1; i >= 0; i--) {
        arr[i] = n % 10;
        n = n / 10;
    }
}

int main()
{
    int n = 78910;
    int size = std::log10(n) + 1; 
    int *arr = new int[size];
 
    int_into_an_array_of_ints(arr, n, size);
 
    for (int i = 0; i < size; i++)
        std::cout << "arr[" << i << "] = " << arr[i] << "\n";
    
    delete [] arr;
}


 
/*
run:
 
arr[0] = 7
arr[1] = 8
arr[2] = 9
arr[3] = 1
arr[4] = 0
 
*/

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