Problem with a user defined function

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#include <stdio.h>
#include <cs50.h>

long enterccno (void);//long type as 14-digit credit card will not fit into the memory as int type
int countdigit (long y);
int checkifAmex (long y);

int main(void)
{
    long y = enterccno();
    printf("credit card no. entered is %ld",y);

    long cc = countdigit(y);
    printf("entered credit card has this number of digit %ld",cc);

    if (cc == 15)
    {
        int z = checkifAmex(cc);
        if (z == 1)
        {
            printf("This is Amex");
            return 0;

        }

    }

    //if (cc == 16)
    //{
       //checkifMastercard
    //}

    //if (cc == 13 or cc == 16)
    //{
        //checkifVisa
    //}

    else
    {
        return 0;
    }
}


long enterccno (void) //It will take void as argument as the function will not initially take any particular long value as input to begin with.
{
    long x = get_long("enter creditcardno");//get_long function by cs50.h leveraged to accept input of creditcard no. from user.
    return x;//stored x value or entered creditcardno transferred inside the main function when entercccno function called.
}

int countdigit (long y)
{
    long x = y;
    int c = 0;
    do
    {
    x = x/10;
    c++;
    }
    while (x > 0);
    return c;
}


int checkifAmex (long y)
{
    long x = y;
    if (x/10000000000000 == 34)
    {
    return 1;
    }
    else
    {
    return 0;
    }
}

			

 

If I enter as input 340000000000000, this divided by 10000000000000 = 34.

So, I anticipate checkifAmex function to return 1 and so print “This is Amex”.

Instead getting this output, which is common to all entered credit card numbers:

 

 

Help appreciated.

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https://edstem.org/us/courses/176/discussion/1706118[learn_press_profile]

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