LinuxQuestions.org - Basic C programming question

Quote:

Originally Posted by lxs602 (Post 6398133)

I also tried using gdb, but it gave an error to do with get_long being not declared.

I faced the same issue after copy and compiling your code.c at localhost using gcc.exe (CYGWIN_NT)
Initially I was not having libcs50 library
Downloaded https://github.com/cs50/libcs50/arch...gs/v11.0.2.zip

Code:

$ unzip.exe libcs50-11.0.2.zip >/dev/null 2>&1

$ cd libcs50-11.0.2

$ make

make: Nothing to be done for 'all'.

$ /usr/bin/cp -i "Makefile" "Makefile.Original"

$# I modified Makefile related to CYGWIN

$ diff Makefile Makefile.Original

17c17

< OS := $(shell /usr/bin/uname | /usr/bin/sed "s/-[0-9]*\.[0-9]-[0-9]*//;")

---

> OS := $(shell uname)

19,24d18

< # CYGWIN_NT

< ifeq ($(OS),CYGWIN_NT)

<      LIB_BASE := $(BASENAME).so

<      LIB_MAJOR := $(BASENAME).so.$(MAJOR_VERSION)

<      LIB_VERSION := $(BASENAME).so.$(VERSION)

<      LINKER_FLAGS := -Wl,-soname,$(LIB_MAJOR)

26c20

< else ifeq ($(OS),Linux)

---

> ifeq ($(OS),Linux)

$ make

#...

install -m 644 src/cs50.h build/include

mv libcs50.so.11.0.2 libcs50.so libcs50.a build/lib

$ /usr/bin/find ./ -type f -name cs50.h

$ mv ./build/include/cs50.h /usr/include/

$ find ./ -type f -name "*.a" -exec grep -l get_long {} \;

./build/lib/libcs50.a

$ find ./ -type f -name "*.so*" -exec grep -l get_long {} \;

./build/lib/libcs50.so.11.0.2

$ mv ./build/lib/libcs50.so.11.0.2 ./build/lib/libcs50.a /usr/lib

$ /usr/bin/gcc.exe -I. -g -Wall 4175719828.c -o ./a.out -lcs50

Inside checkfunction
if( 0 == x || 0 > i )
{
break;
}
to prevent core dump issue
I have taken base version from https://github.com/jhustles/c_verify...editCardType.c

Code:

#include <cs50.h>

#include <math.h>

#include <stdio.h>

int main(void)

{

        // Always initialize the variable

        long DebitCreditCardNum = 0;

        int sumOfProductDigits = 0;

        int sumOfNonProductDigits = 0; // sum of digits that are not products

        int checkSum = 0;

        long NumModulusTen = 0;

        long SecondModulusTen = 0;

        // Prompt user for credit card input.

        do

        {

                DebitCreditCardNum = get_long( "Number: " );

                // printf( "%li\n", DebitCreditCardNum);

        }

        while( 0 > DebitCreditCardNum );

        sumOfProductDigits = 0;

        sumOfNonProductDigits = 0;

        long ccNumbers1 = DebitCreditCardNum; // Used for checkSum

        long ccNumbers2 = DebitCreditCardNum; // Used for card validation

        while( 0 < ccNumbers1 )

        {

                NumModulusTen = ccNumbers1 % 10; // out: 4

                sumOfNonProductDigits += NumModulusTen; // add 4

                // printf( "Adding %li\n to sumOfNonProductDigits\n", NumModulusTen);

                ccNumbers1 = ccNumbers1 - NumModulusTen; // minus the last digit

                ccNumbers1 = ccNumbers1 / 10; // reduce by one last digit by dividing by 10

                // printf( "Updated ccNumbers1 after is: %li\n", ccNumbers1);

                // printf( "###########################\n" );

                // Second Number to iterate thru

                SecondModulusTen = ccNumbers1 % 10; // out: 1

                // printf( "Here's SecondModulusTen: %li\n \n", SecondModulusTen);

                // printf( "Sum Of Product Digits: %i\n \n", sumOfProductDigits);

                // printf( "Sum Of Non-Product Digits: %i\n \n", sumOfNonProductDigits);

                ccNumbers1 = ccNumbers1 - SecondModulusTen;

                ccNumbers1 /= 10;

                if( 9 < SecondModulusTen * 2 ) // if there's two digits you'll have to add each digit

                {

                        // Product result is double digits. Repeat the same thing to split numbers

                        // and reduce the ccNumbers1

                        SecondModulusTen = SecondModulusTen * 2;

                        int numSlice = SecondModulusTen % 10; // split by getting the last digit

                        sumOfProductDigits += numSlice;

                        sumOfProductDigits += ((SecondModulusTen - numSlice) / 10); // add to products sum

                }

                else

                {

                        // multiply the digit by 2 and add to sumOfProductDigits

                        SecondModulusTen = SecondModulusTen * 2;

                        sumOfProductDigits += SecondModulusTen;

                }

        }

        checkSum = sumOfProductDigits + sumOfNonProductDigits;

        // printf( "CHECK SUM: %i\n", checkSum);

        // Algorithm to check if card is valid:

        if( 0 == checkSum % 10 )

        {

                bool amex = false;

                bool mastercard = false;

                bool visa = false;

                amex =

                        (ccNumbers2 >= 340000000000000 && ccNumbers2 < 350000000000000) ||

                        (ccNumbers2 >= 370000000000000 && ccNumbers2 < 380000000000000);

                mastercard =

                        (ccNumbers2 >= 5100000000000000 && ccNumbers2 < 5600000000000000);

                visa =

                        (ccNumbers2 >= 4000000000000 && ccNumbers2 < 5000000000000) ||

                        (ccNumbers2 >= 4000000000000000 && ccNumbers2 < 5000000000000000);

                if(amex)

                {

                        printf( "AMEX\n" );

                }

                else if(mastercard)

                {

                        printf( "MASTERCARD\n" );

                }

                else if(visa)

                {

                        printf( "VISA\n" );

                }

                else

                {

                        printf( "%lu INVALID_NUMBER\n", DebitCreditCardNum );

                }

        }

        else

        {

                printf( "%lu INVALID NUMBER\n", DebitCreditCardNum );

        }

        return 0;

}

/*

01. Always initialize variables

02. Alwayse beter to write return/return0 based on the functions.

03. Replace:

        while (DebitCreditCardNum < 0);

        ...

        if

        ...

        else if

        ...

        for

With:

        while( 0 > DebitCreditCardNum );

        ...

        if

        ...

        else if

        ...

        for

Reason: new programmers may assign using:

        while( DebitCreditCardNum = 0 );

I have taken following ATM card numbers from internet images:

$ ./a.out

Number: 5333619503715702

MASTERCARD

$ a.out

Number: 5555555555554444

MASTERCARD

$ a.out

Number: 5454545454545454

MASTERCARD

$ a.out

Number: 4444333322221111

VISA

*/

$ mv verifyCreditCardType.c ValidateCardType.c
$ /usr/bin/gcc.exe -g -Wall ValidateCardType.c -o ./a.out -lcs50