Rough times trying to convert string to integers array [closed] - c

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Basically the program will ask for user credit card number, capture it inside a string, convert a string to an integer array (so I can validate credit card number, for later digit sums and multiplying).
I need a variable with integers array and the code below stores ASCII values.
Tried reading lots of posts, but didn't get it.
I'd appreciate any help, so I could sleep again =)
Cordially,
#include <cs50.h>
#include <stdio.h>
#include <string.h>
int main (void)
{
string cc_string;
printf("Please enter a credit card number:\n");
//Captures credit card string
cc_string = GetString();
// Array of credit card digits integers
int cc_digits[16];
for (int i = 0; i<= 15; i++)
{
cc_digits[i] = (int) cc_string[i];
//Just checking what value has been stored
printf("position %d with %d \n", i, cc_digits[i]);
}
//to be continued
}

Answer 1

Instead of cc_digits[i] = (int) cc_string[i] try cc_digits[i] = cc_string[i] - '0' If you just cast to int you'll get the ASCII code for the character, but if you subtract the code of character 0 then you should get the actual digit.

Answer 2

Instead of casting to int with (int), use atoi()

Answer 3

Found the solution, want to share with you guys.Thank you all for the help, time and learnings.
#include <cs50.h>
#include <stdio.h>
int main (void)
{
long long cc_num;
int array_dig[15];
int static sum_evens, sum_odds, sum_tot, valid = 0;
printf("Enter your credit card number for validation: \n");
cc_num = GetLongLong();
for (int i=15; i >= 0; i--)
{
array_dig[i] = cc_num % 10;
cc_num = cc_num / 10;
//Sanity check
printf("pos %d = %d\n", i, array_dig[i]);
}
//Summing digits
for (int j=0; j < 16; j++)
{
if (j % 2 == 0)
{
sum_evens += array_dig[j];
//Sanity check
printf("sum_evens = %d/n", sum_evens);
}
else if (j % 2 == 1)
{
if (array_dig[j] < 5)
{
sum_odds += 2 * array_dig[j];
//Sanity check
printf("sum_odds for char < 5 = %d\n", sum_odds);
}
else
{
sum_odds += (2 * array_dig[j]) % 10 + 1;
//Sanity check
printf("sum_odds for char >= 5 = %d\n", sum_odds);
}
}
}
sum_tot = sum_evens + sum_odds;
//Validation (if sum % 10 = 0 it is valid)
valid = sum_tot % 10;
printf("sum_tot = %d, valid = %d \n", sum_tot, valid);
if (valid % 10 == 0)
{
printf("Valid credit card \n");
}
else
{
printf("Invalid credit card\n");
}
}

Answer 4

Not so soon. =(
Program looses precision when passes values (digits) to the long long variable cc_num.
#include <cs50.h>
#include <stdio.h>
#include <string.h>
int main (void)
{
long long cc_num;
char cc_num_str[15];
int static sum_evens, sum_odds, sum_tot, valid = 0;
int static size;
do
{
printf("Enter your credit card number for validation: \n");
cc_num = GetLongLong();
sprintf(cc_num_str, "%lld", cc_num);
size = strlen (cc_num_str);
}
while (cc_num < 1 || cc_num > 9999999999999999 || size < 13 || size > 16);
int array_dig[size];
for (int i = size - 1; i >= 0; i--)
{
array_dig[i] = cc_num % 10;
cc_num = cc_num / 10;
//Sanity check
printf("pos %d = %d\n", i, array_dig[i]);
}
//Summing digits
for (int j=0; j < size; j++)
{
if (j % 2 == 0)
{
sum_evens += array_dig[j];
//Sanity check
printf("sum_evens = %d/n", sum_evens);
}
else if (j % 2 == 1)
{
if (array_dig[j] < 5)
{
sum_odds += 2 * array_dig[j];
//Sanity check
printf("sum_odds for char < 5 = %d\n", sum_odds);
}
else
{
sum_odds += (2 * array_dig[j]) % 10 + 1;
//Sanity check
printf("sum_odds for char >= 5 = %d\n", sum_odds);
}
}
}
sum_tot = sum_evens + sum_odds;
//Validation (if sum % 10 = 0 it is valid)
valid = sum_tot % 10;
printf("sum_tot = %d, valid = %d \n", sum_tot, valid);
if (valid % 10 == 0)
{
//code that will verifies card type (to be written)
printf("Valid credit card \n");
}
else
{
printf("Invalid. \n");
}
return 0;
}
Here is the output:
Enter your credit card number for validation:
1234567809874366
pos 15 = 8
pos 14 = 3
pos 13 = 6
pos 12 = 9
pos 11 = 5
pos 10 = 8
pos 9 = 9
pos 8 = 0
pos 7 = 8
pos 6 = 7
pos 5 = 6
pos 4 = 5
pos 3 = 4
pos 2 = 3
pos 1 = 2
pos 0 = 1
sum_evens = 1/nsum_odds for char < 5 = 4
sum_evens = 4/nsum_odds for char < 5 = 12
sum_evens = 9/nsum_odds for char >= 5 = 15
sum_evens = 16/nsum_odds for char >= 5 = 22
sum_evens = 16/nsum_odds for char >= 5 = 31
sum_evens = 24/nsum_odds for char >= 5 = 32
sum_evens = 33/nsum_odds for char >= 5 = 35
sum_evens = 36/nsum_odds for char >= 5 = 42
sum_tot = 78, valid = 8
Invalid.