Question

How to convert an array of digits to an integer add 1 and convert it back to an array of digits in C

Answer 1

#include <stdio.h>
 
int convert_array_of_digits_to_int_number(int arr[], int arr_size) {
    int n = 0;
      
    for (int i = 0; i < arr_size; i++) {
        n = n * 10 + arr[i];
    } 
     
    return n;
}

void convert_int_number_to_array_of_digits(int digits[], int n, int size) {
    int i = size - 1;
      
    while (n > 0) {
        digits[i] = n % 10;
        n = n / 10;
        i--;
    }
}
 
int main() {
    int arr[] = {9, 4, 6, 9};
    int arr_size = sizeof(arr) / sizeof(arr[0]);
     
    int n = convert_array_of_digits_to_int_number(arr, arr_size);
    
    n++;
    
    convert_int_number_to_array_of_digits(arr, n, arr_size);
     
    printf("n = %d\n", n);
    
    for (int i = 0; i < arr_size; i++) {
        printf("%d, ", arr[i]);
    }
     
    return 0;
}
 
 
 
 
/*
run:
 
n = 9470
9, 4, 7, 0,
 
*/

 

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