Questions tagged [credit]
153 questions
3
votes
2
answers
13k
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Finding the nth digit for credit card number
I'm having a hard time trying to find the 2nd to last digit of the user's credit card number, since that's the starting point for Luhn's algorithm. Is there a way to convert a long to an array and ...
- 45
3
votes
1
answer
193k
views
Why do I get the "invalid operands to binary expression" error?
While trying to solve credit, I get the following error
rem and number1 are declared as long and even if I change them to int, I still get the same error.
Please provide a solution and explain what ...
- 206
3
votes
1
answer
379
views
Why Does credit Fail Passing check50 Tests?
When I input the credit card numbers that check50 inputs in its tests to my program myself, It correctly identifies the numbers as expected. However, when I run check50, it's not identifying correctly....
2
votes
1
answer
4k
views
Credit from CS50 2018 week 1 walkthrough
Hi i am a beginner and i have been trying to solve this set but with no avail.
I tried to use what was taught in the first lesson and did search for some help online when i encounter errors. However, ...
- 23
1
vote
2
answers
430
views
pset1 credit, need advice
I actually try to do the Credit Task back from pset1.
So far i understand how the calculation for the checksum validation of the
Credit Card Number works, and could do it on Paper.
The Problem, i ...
- 31
1
vote
4
answers
1k
views
Finding the products' digit and adding them individually
Separating the products' digits and adding them up is giving me trouble. For example for this credit card number: (1234567), 12, 8, and 4 would be the result of multiplying every other digit by 2. How ...
- 45
1
vote
1
answer
635
views
credit - Why this AMEX and MASTERCARD numbers are considered invalid?
I have compiled my version of credit, anyway check50 throws 2 fails during its check. Lines with numbers where it fails are:
:( identifies 369421438430814 as INVALID
expected "INVALID\n", not ...
- 163
1
vote
3
answers
144
views
Why is this while loop generating errors
I'm trying to get a 15 or 16 digits numbers (integers) from users and then using a do while loop to check if the user entered a valid number, otherwise, they will be re-ask to enter the number.
THE ...
1
vote
2
answers
616
views
Credit.c is my nemesis
I have no experience programming, and English is not my first language so I'm struggling a lot with this particular problem.
In "credit.c" you have to prompt the user for a credit card number and ...
1
vote
1
answer
5k
views
Pset 1 Credit Card ( help needed )
Update # attempt 2:
I am not getting valid output, code complies fine.
What am I missing?
code follows:
including cs.50 and stdio ( i don't think i need math )
bool checksum( long long cc); // for ...
1
vote
1
answer
40
views
CS50x PSET1 Credit <class 'pexpect.exceptions.EOF'>
So regarding Pset 1 Credit, I'm having this issue with Check50
My code identifies the card, but there's some error when input given at shorter length:
My code are the following:
#include <cs50.h&...
- 11
1
vote
1
answer
2k
views
Pset6 credit python Problem
I try to convert my Credit Solution from C to Python now.
But on Line 19 ( doubleCheck = ccNumber[i] * 2 ) i always get the error "TypeError: 'int' object is not subscriptable"!
How can i fix this?
...
user23533
1
vote
2
answers
165
views
error at while loop cs50 Pset1 credit
I am getting an error at while loop it says
error: '&&' within '||' [-Werror,-Wlogical-op-parentheses]
while((credit % 10 >= 0) && (i < 15) || (i < 16))
here is my ...
1
vote
1
answer
240
views
problem with pset6 python credit
Below is my code:
[hidden code]
output is:
Enter the card number: 378282246310005
firstTwo 37; firstOne 3; cardlen 15
MASTERCARD
note: it shows MASTERCARD instead of AmEx..Why?
- 13
1
vote
1
answer
52
views
Credit : the checksum is correct for <10 digits, but for14,15,16 digits getting negative checksum
The checksum is correct for less than 10 digits but for 14-16 digits it is coming back negative. What am I doing wrong?
#include <cs50.h>
#include <stdio.h>
#include <math.h>
int ...
- 13
1
vote
1
answer
333
views
problem with credit with this numbers (369421438430814 & 5673598276138003)
I just finished solving the credit problem and regularly used check50 to see my results, and then this happened.
check50 sees that these numbers :
369421438430814
5673598276138003
are invalid, even ...
1
vote
1
answer
9k
views
error: result of comparison against a string literal is unspecified (use strncmp instead) and Check50 showing error on credit problem
I've submitted my credit problem after testing with possible values and everything seems to work just fine as planned, except that I got some errors that certain numbers could not be tested as INVALID ...
1
vote
1
answer
103
views
Incorrect mastercard number in pset1 [duplicate]
by lunh algoritm result of calculating 5105105105105100 will be 25 and it means that this card is invalid, but check50 output this:
:( identifies 5105105105105100 as MASTERCARD
expected "...
- 13
1
vote
2
answers
96
views
Problem With Check50 for problem set "Credit"
I'm currently working on week 6 python and the problem sets are the same to that of pset 1 just with python instead of C. So when I decided to write it I saw that my code in C was extremely bad so I ...
- 13
1
vote
1
answer
49
views
CheckSum in credit pset1
as in the code given below i want to multiply 1 by 2 then delete it and so on but i don't how to do that i made the first steps to delete the last number by using %10 then show it with the /10 i hope ...
1
vote
1
answer
86
views
Week 1 - Problem concerning question on 'credit'
Consider:
#include <cs50.h>
#include <stdio.h>
int main (void)
{
//User's Input
long n = get_long("Number: ");
int sum_of_odds = 0;
int sum_of_evens = 0;
...
- 11
1
vote
1
answer
33
views
Making code neater: a way to reduce repeated logical operators?
For CS50 pset1 Credit I'm using repeated logical-OR operators (||) to work out the validity and card brand of a credit card number. When I evaluate the style of my code using style50 it says to insert ...
- 15
1
vote
0
answers
787
views
Every 2nd digit on Pset1 Credit problem: Tldr bolded
Im struggling with manipulating the string of numbers in the credit problem. I've figured out how to divide the initial input number by 10 (*100 each iteration) then mod % by 10 in order to access the ...
- 11
0
votes
2
answers
26k
views
How to convert the digits of a number into elements of array?
For example in pset1 hacker edition program asks user to input the number of credit card.
Imagine that a digits are: 1234567890
So can anyone tell me does it possible to convert this number into ...
- 1
0
votes
1
answer
2k
views
Credit GetLongLong Issue
I'm having issues using the GetLongLong function. For some reason the output I get doesn't match the input I put in. Here, is my code.
#include <studio.h>
#include <cs50.h>
int main(void)...
- 1
0
votes
1
answer
2k
views
I keep getting "expected EOF" when I use check50
this is the message
identifies 4111111111111113 as INVALID
expected EOF, not "INVALID"
this is the code
#include <cs50.h>
#include <stdio.h>
#include <string.h>
#include &...
- 31
0
votes
1
answer
138
views
credit.c project in hacker1 I keep having this error?
While trying to compile the codes uploaded I keep having this error which I couldn't understand!
0
votes
1
answer
710
views
Credit - Why Does it Fail Passing check50?
When sending my code to Check50, all the Credit Card checks go through ok but one:
:( identifies 4062901840 as INVALID
expected "INVALID\n", not "VISA\n"
But doing the steps:
1) Multiply every ...
- 7
0
votes
3
answers
1k
views
pset 1 credit.c invalid cards are valid by cs50
It was said that you can verify if the credit card number is valid by using Luhn’s algorithm. If you done mathematical operations right, after them, you know if the card is valid if the last digit in ...
- 113
0
votes
2
answers
241
views
credit.c frustration
Im considering skipping :( I dont really understand why it always prints INVALID4....
#include <stdio.h>
#include <cs50.h>
#include <math.h>
int main (void)
{
//Initialize a ...
0
votes
2
answers
128
views
PSET 1 Credit; Sometimes Check50 works and other times it doesn't
Why does Check50 work for certain credit numbers and not others? I ran debug and found that for some credit numbers and not others it may randomly be always one away from a multiple of 10 preventing ...
- 5
0
votes
1
answer
199
views
PSET1 - Credit: Check50 says wrong what should be right
Someone with the same problem? I have a 16 digit number starting with a 4 and my code identifies it correct as VISA\n, but the check50 says it has to be INVALID\n. What could cause this strange ...
- 3
0
votes
1
answer
586
views
Can't use get_long_long();
So somehow I cant use the get_long_long(); function. It lets me declare the variable, but I cant get any user input for it.
Here's my code:
#include <stdio.h>
#include <cs50.h>
#include &...
- 107
0
votes
1
answer
207
views
PSET1 - Credit HELP
I am now working on the first part of credit, and is currently checking the validity of the number given. I separated it into two parts, one where I summed the doubled digits, and one where I summed ...
- 13
0
votes
1
answer
2k
views
pset1 | error: invalid operands to binary expression ('long long *' and 'int')
Here are snippets of my code:
long long card = get_long_long();
long long *FindLength = *card;
while (FindLength != 0)
{
FindLength = FindLength / 10;
counterCardLength++;
}
And ...
- 15
0
votes
1
answer
431
views
I have problems applying Credit in python
I try to translate my code from c to python. I review the code several times and I think that is equal, but the program don't works despite in c works prefectly. This is my implementation:
"""Know ...
- 27
0
votes
1
answer
411
views
long long to array, how did you do?
I want to know new ways to do it,
this is my solution.
arr[nccard - i] = (long long)(ccard / pow(10, i - 1)) % 10;
0
votes
2
answers
699
views
errors I cant understand in credit.c can anyone explain?
I am taking the number as a string(n) and then trying to convert the string into ints to add them like this:
else if(strlen(n)==15 && (n[1]==3&&(n[2]==4||n[2]==7)))
{
for(i=14;i&...
0
votes
1
answer
30
views
Week 1 Credit, two visa cards #s not working
I've been stumped on Credit for a few weeks, I've learned a LOT in writing my code and I have fixed many errors. My code now passes all the checks except for these two errors and I cannot figure out ...
0
votes
1
answer
29
views
How to Solve : expected identifier or '('
here is my code:
#include <stdio.h>
#include <cs50.h>
//Declaring User-Defined Functions
int last_digit(int sum3);
int main(void)
{
//Promting the user for credit card number
...
- 3
0
votes
2
answers
48
views
pset1-credit I can't find the issue with my code
the program prints invalid for valid card I know that my mistake is probably really dumb, but I can't find it (sorry for bad english)
#include <cs50.h>
#include <stdio.h>
int main(void)
{
...
- 3
0
votes
1
answer
41
views
pset1 credit 2023 , do while loop with arrays/intervals
#include <cs50.h>
#include <stdio.h>
int main(void)
{
long n;
do
{
n = get_long("13 digits or at max 15, 16 card number: ");
}
while(n < ...
- 27
0
votes
1
answer
40
views
there is a logical error I can't really catch up with
Output:
Results for cs50/problems/2022/x/credit generated by check50 v3.3.7
:) credit.c exists
:) credit.c compiles
:) identifies 378282246310005 as AMEX
:) identifies 371449635398431 as AMEX
:) ...
0
votes
1
answer
98
views
credit.c I don't understand how to fix my code
I've been trying to figure out what's wrong with my code. I used printf so I could confirm whether or not the value of N is correct but it's coming out as completely different as what I would expect ...
- 1
0
votes
1
answer
145
views
Need help with the Credit Problem for Week 1
I have signed up for this year's CS50x, and I am stuck on the problem where we are meant to validate a credit card. The problem requires that we check the amount of digits, the first digits and use ...
- 1
0
votes
1
answer
69
views
credit pset1 cs50 sum while loop
I was doing the credit problem with the visa test card in the page: 4003600000000014
It passed that test, however in other tests it doesn't pass.
I think it's a matter of the sum that it can't compute ...
- 1
0
votes
1
answer
118
views
Credit Card Check
So I am on pset6 trying to implement the credit card check.
I've already completed working through the numbers and am not having any issue with the actual algorithm.
But for some reason my if ...
- 117
0
votes
1
answer
183
views
Credit (Pset1) - Checksum problem
so I have a problem with the Credit exercise from pset1. I updated my code today after realizing that I didn't split up the digits of the product of the current digit in the card number and 2 and ...
- 137
0
votes
1
answer
107
views
pset6 credit help with calculations in python
I am trying to convert my credit solution from C to python, but for some reason it is not working. Attached is my code and the problems
from cs50 import get_int
card, a, m, v = False, False, False, ...
- 5
0
votes
1
answer
65
views
credit pset1 bruteforcing doesn't work
I was trying out credit and tried to write a code for all 15 digit cards so if a AMEX card exists it should work in theory. However even with valid cards I'm getting the input invalid. I have not ...
- 156