Questions tagged [credit]

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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 ...
3
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1answer
126k 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 ...
2
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1answer
359 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
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1answer
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, ...
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2answers
411 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 ...
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4answers
964 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 ...
1
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1answer
336 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 ...
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3answers
127 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
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1answer
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 ...
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1answer
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? ...
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2answers
144 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 ...
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1answer
224 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?
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1answer
471 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
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1answer
80 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 "...
1
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1answer
30 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 ...
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0answers
706 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 ...
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2answers
17k 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 ...
0
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1answer
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)...
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1answer
135 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!
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3answers
870 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 ...
0
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2answers
239 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 ...
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2answers
59 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 ...
0
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1answer
365 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 &...
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1answer
82 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 ...
0
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1answer
408 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 &...
0
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1answer
186 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 ...
0
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1answer
1k 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 ...
0
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1answer
410 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 ...
0
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1answer
383 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 ...
0
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1answer
403 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;
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2answers
660 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&...
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1answer
34 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 ...
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1answer
61 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 ...
0
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1answer
60 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 ...
0
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1answer
46 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, ...
0
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1answer
48 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 ...
0
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2answers
77 views

Can anyone help me troubleshoot my code for the CS50 Credit problem? (**not trying to cheat, just need some help!)

This is the code I have written in c for the cs50 credit pset 1 problem. I am checking the length of numbers entered, and the first digits (AMEX 15 digits, starts with 34 or 37; MC 16 digits, starts ...
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1answer
74 views

Question about Pset1 - credit

I had work on the credit for 3 hours, and I had reach to most of the function - and I checked that the number received from: Luhn (a) last digit(c) and digit count (cc) are right by using ...
0
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1answer
57 views

PSET6 Credit - checksum not giving the correct number

list1 = list(input("Number: ").strip()) even_count, odd_count, count = 0, 0, 0 # if the length is even if len(list1)%2 == 0: # iterating each number in list for num in list1: ...
0
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1answer
25 views

Week 1 Credit; Not Creating Variable

I'm starting the week 1 credit problem, however, when trying to set together every second digit it simply does not print. Could you help me identify where I went wrong? Thanks! #include <stdio.h>...
0
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1answer
37 views

ProblemSet1 - Another Credit.c issue - Can't convert the floating value of my variables into an integer value

I was almost finishing my code when I got stuck with a strange problem. I've asked a question a few hours ago and someone answered, so I manage to fix that issue. But unfortunelly I got stuck in ...
0
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1answer
32 views

ProblemSet1 - Credit.c - Issues assigning the sum of the numbers on a variable

So I coded the first lines of the Luhn's Algorithm and tried to print the values of some of my variables to be sure they were doing exactly what I want it. For my surprise they weren't. And I were ...
0
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1answer
47 views

CS50 Credit - again a scope problem

I think I almost finished the credit problem set, however, I have another scope problem. I think it is really simple. After the checksum, the code is not working anymore. If I put extra braces by the ...
0
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1answer
19 views

Scope problem - not print the test results

I have trouble with my scope (PS1, credit) I am using two while loops and to test the result, i print results in between. This code does not print the second printf. I think it is a scope problem but ...
0
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1answer
68 views

pset6 credit the sum is not end with zero and check count right how

the Luhn’s Algorithm in 378282246310005 = 48 and in 371449635398431 = 76 so how not INVALID it must end with zero so the two number must be INVALID
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1answer
69 views

I am not getting the correct output when i enter David's card number in credit

This is my code: #include <stdio.h> #include <cs50.h> #include <math.h> int main(void) { int x, y, z, p, q, r, d, e; int k = 0; int s = 0; long A; long n = ...
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1answer
344 views

Pset 1: Credit problem - Checksum?

I'm having trouble with the checksum in the #credit problem. I have no clue on how to operate specific digits within the credit card number (specifically, multiplying the digits in the odd positions ...
0
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1answer
63 views

pset1 credit formula to extract digits keeps returning 0 (potential data type issue?)

Below is the block of code that i have issue with. I'm using this method to extract the digits: num[i] = (num % pow(10, i))/pow(10, i-1). The pow1 and pow2 variables print out correctly, but "digit" ...
0
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1answer
107 views

Credit.py Invalid Error

For Pset6 Sentimental/Credit, my code keeps showing a result of INVALID\n no matter what is passed in. Debug50 is not working in Python, so I was not able to work through the lines one by one. Any ...
0
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1answer
112 views

pset1 - credit - if-else statement issue

I have written a (clumsy) solution to the credit pset1. However, the solution only works for "Mastercard" credit card numbers (i.e. 5555555555554444). For "Visa" and "Amex" my code does return the ...