CS50：credit.c 中的致命错误

Question

我是一个真正的新程序员，之前写过3个代码！（包括你好世界！）我真的试图找出一种算法来帮助我找出 credit.c 程序，但我的程序一直出现运行错误。现在的代码非常混乱，但如果我先了解它的功能，我会尝试更好地设计它。这是代码，

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

int main(void);
long long CCno;//since int cant hold this long number
{  
    do
    {
      x = get_long_long("Number: ") //asks for user to input cc number
    }
    while (x < 0 || x > 9999999999999999); //returns a non zero number
}


int numcount = 0;
int numcount = (x == 0) ? 1 : (log(x) + 1);
//calculate checksum

//Finds alternate numbers and multiplies with 2
        int digit1 = (((x % 100) / 10) * 2);
        int digit2 = (((x % 10000) / 1000) * 2);
        int digit3 = (((x % 1000000) / 100000) * 2);
        int digit4 = (((x % 100000000) / 10000000) * 2);
        int digit5 = (((x % 10000000000) / 1000000000) * 2);
        int digit6 = (((x % 1000000000000) / 100000000000) * 2);
        int digit7 = (((x % 100000000000000) / 10000000000000) * 2);
        int digit8 = (((x % 10000000000000000) / 1000000000000000) * 2);

//Find the other remaining numbers
        int digit9 = ((x % 10) / 1);
        int digit10 = ((x % 100) / 10);
        int digit11 = ((x % 1000) / 100);
        int digit12 = ((x % 10000) / 1000);
        int digit13 = ((x % 100000) / 10000); 
        int digit14 = ((x % 1000000) / 100000);
        int digit15 = ((x % 10000000) / 1000000);
        int digit16 = ((x % 100000000) / 10000000);

        int sum1 = ((digit1 % 10) + (digit1 / 10));
        sum1 = (sum1 + (digit2 % 10)) + (digit2 / 10);
        sum1 = (sum1 + (digit3 % 10)) + (digit3 / 10);
        sum1 = (sum1 + (digit4 % 10)) + (digit4 / 10);
        sum1 = (sum1 + (digit5 % 10)) + (digit5 / 10);
        sum1 = (sum1 + (digit6 % 10)) + (digit6 / 10);
        sum1 = (sum1 + (digit7 % 10)) + (digit7 / 10);
        sum1 = (sum1 + (digit8 % 10)) + (digit8 / 10);

int checksum = (sum1 + digit9 + digit10 + digit11 + digit12 + digit13 + digit14 + digit15 + digit16)

//check first two digits

    if
    {
        (numcount == 15)
        (digit1 == 3 && digit2 == 4 || 7)
        printf("AMEX");
    }

    if
    {
        (numcount == 13 || 16)
        (digit1 == 4)
        printf("VISA");
    }
    if
    {
        (numcount == 16)
        (digit1 == 5 && digit2 == 1 || 2 || 3 || 4 || 5)
        printf("MASTERCARD");
    }
    else
    {
        printf("INVALID");
    }

请帮我找出错误！！ edit- 现在所有其他错误都已更正，还有一个错误。

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

int main( void ); 

long long x;//since int cant hold this long number
{
    do
    {
      x = get_long_long("Number: ") //asks for user to input cc number
    }
    while (x < 0 || x > 9999999999999999); //returns a non zero number



   int numcount = 0;
   int numcount = (x == 0) ? 1 : (log(x) + 1);
    //calculate checksum

    //Finds alternate numbers and multiplies with 2
        int digit1 = (((x % 100) / 10) * 2);
        int digit2 = (((x % 10000) / 1000) * 2);
        int digit3 = (((x % 1000000) / 100000) * 2);
        int digit4 = (((x % 100000000) / 10000000) * 2);
        int digit5 = (((x % 10000000000) / 1000000000) * 2);
        int digit6 = (((x % 1000000000000) / 100000000000) * 2);
        int digit7 = (((x % 100000000000000) / 10000000000000) * 2);
        int digit8 = (((x % 10000000000000000) / 1000000000000000) * 2);

//Find the other remaining numbers
        int digit9 = ((x % 10) / 1);
        int digit10 = ((x % 100) / 10);
        int digit11 = ((x % 1000) / 100);
        int digit12 = ((x % 10000) / 1000);
        int digit13 = ((x % 100000) / 10000); 
        int digit14 = ((x % 1000000) / 100000);
        int digit15 = ((x % 10000000) / 1000000);
        int digit16 = ((x % 100000000) / 10000000);

        int sum1 = ((digit1 % 10) + (digit1 / 10));
        sum2 = (sum1 + (digit2 % 10)) + (digit2 / 10);
        sum3 = (sum1 + (digit3 % 10)) + (digit3 / 10);
        sum4 = (sum1 + (digit4 % 10)) + (digit4 / 10);
        sum5 = (sum1 + (digit5 % 10)) + (digit5 / 10);
        sum6 = (sum1 + (digit6 % 10)) + (digit6 / 10);
        sum7 = (sum1 + (digit7 % 10)) + (digit7 / 10);
        sum8 = (sum1 + (digit8 % 10)) + (digit8 / 10);

int checksum = (sum1 + sum2 + sum3 + sum4 + sum5 + sum6 + sum7 + sum8 + digit9 + digit10 + digit11 + digit12 + digit13 + digit14 + digit15 + digit16)

//check first two digits

    if
    {
        (numcount == 15)
        (digit1 == 3 && digit2 == 4 || 7)
        printf("AMEX");
    }

    if
    {
        (numcount == 13 || 16)
        (digit1 == 4)
        printf("VISA");
    }
    if
    {
        (numcount == 16)
        (digit1 == 5 && digit2 == 1 || 2 || 3 || 4 || 5)
        printf("MASTERCARD");
    }
    else
    {
        printf("INVALID");
    }
}

这是错误信息-

clang -fsanitize=signed-integer-overflow -fsanitize=undefined -ggdb3 -O0 -std=c11 -Wall -Werror -Wextra -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable -Wshadow 
   credit.c  -lcrypt -lcs50 -lm -o credit
credit.c:8:1: error: expected identifier or '('
{
^
1 error generated.
<builtin>: recipe for target 'credit' failed
make: *** [credit] Error 1

Answer 1

这是一个问题：

int main(void); // <-- get rid of this semicolon
long long CCno; // <-- this either needs to be declared above main, or between
{               //     the {} of the function body
    do
    {
      x = get_long_long("Number: ") //asks for user to input cc number
    }
    while (x < 0 || x > 9999999999999999); //returns a non zero number
}

第一步，重写如下：

int main( void )
{
  long long CCNo;

  // do loop as written above

  // everything involving numcount, digit, etc.
}

还有很多问题，但这至少应该让您克服一些错误。

CS50：credit.c 中的致命错误

CS50: fatal errors in credit.c

c

cs50

luhn