Access Violation

This is a discussion on Access Violation within the C Programming forums, part of the General Programming Boards category; Originally Posted by tabstop Which line? int *digits is fine. struct integer *num[length] is most assuredly not. Oh, that one. ...

  1. #61
    Confused College Student Graham Aker's Avatar
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    Quote Originally Posted by tabstop View Post
    Which line? int *digits is fine. struct integer *num[length] is most assuredly not.
    Oh, that one. Yeah, I can take the * out there. >.>;;

  2. #62
    In my head happyclown's Avatar
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    Graham Aker, can you post the contents of the file that you are trying to read?

    EDIT: if you haven't already done so in this long thread.
    OS: Linux Mint 13(Maya) LTS 64 bit.

  3. #63
    Confused College Student Graham Aker's Avatar
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    Aright, I removed the *, and I got an error on line 39 about an incompatable type in argument 3 of 'readnum'. How would I fix this?

    Oh, yeah, the code:
    Code:
    #include <stdlib.h>
    #include <stdio.h>
    
    #define big 2000
    #define length 20
    
    struct integer {
    	int* digits;
    	int size;
    };
    
    int i, j, k, stringnum;
    
    int readnum(int stringnum, char* numbr, struct integer *emp);
    
    int main(){
          FILE *ifp;
          char numbr[big];
          struct integer num[length];
    
    //Read in the file      
          ifp = fopen("bigint.txt", "r");
    
    //Scan for the number of strings
          fscanf(ifp, "%d", &stringnum);
          
    //Read in the numbers
          for (k=0; k<stringnum; k++){
               fscanf(ifp, "%s", numbr);  
               readnum(k, numbr, num[k]);
          }
                           
    //Read the array
          printf("The arrays are: \n");
          for (k=0; k<stringnum; k++){
               for (i=0; i<j; i++)
                   printf ("%d ", num[k].digits[i]);
          printf("\n");
          }
    
          system("PAUSE");
          return 0;
    };
    //Define functions
    int readnum(int stringnum, char* numbr, struct integer *emp){
    
          int arraysize = strlen(numbr);      
          emp->digits = malloc(sizeof(*emp->digits) * arraysize);
          
    //Move the integer into the array      
          for(i=arraysize, j=0; i>-1; i--){
               if(isdigit(numbr[i])){
                   emp->digits[j++] = numbr[i] - '0';
               }
          }
          emp->size = j;
    };
    EDIT: Durr, the input file. Here THAT is:
    Code:
    2
    31843694157942314379137864165
    2986783975917945029875942976

  4. #64
    and the Hat of Guessing tabstop's Avatar
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    Pass the address of the specific thing you want to read to the function.

  5. #65
    In my head happyclown's Avatar
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    Quote Originally Posted by Graham Aker View Post

    //Scan for the number of strings
    fscanf(ifp, "%d", &stringnum);

    This doesn't look right.

    Code:
    int stringnum;
    If the file had this number:

    123456

    Code:
    fscanf(ifp, "%d", &stringnum);
    Would result in stringnum = 123456;

    If your intention is to determine how many strings(lines) there are in the file, use fgets, which gets a string(line) at a time, then use a counter to count how many strings were read(using a loop).
    OS: Linux Mint 13(Maya) LTS 64 bit.

  6. #66
    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by happyclown View Post
    This doesn't look right.

    Code:
    int stringnum;
    The first line of the file has the number of numbers in it.

  7. #67
    Confused College Student Graham Aker's Avatar
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    Quote Originally Posted by tabstop View Post
    Pass the address of the specific thing you want to read to the function.
    ...Uh, what? That's a bit vague...

    Oh, and joy, I just found what his input file was. Posting that now...

    Code:
    3
    1 8888888888 2222222222
    2 9999999999 10000000000
    2 10000000000 9999999999
    In those three bottom lines, I'm guessing the first number is the option he wants run (1 for addition, 2 for subtraction, and 3 for comparison, based off the sample output) and the following numbers are the two strings. This actually saves me a bit of trouble along the lines of storing the data in a structure array since it's different for each option and it just prints right there, but it still means I screwed up bad and need to rewrite a decent amount of the code...

    And he even gave me the funtions he wanted to use, too:
    Code:
    //Preconditions: the first parameter is string that stores
    //               only contains digits, doesn't start with
    //               0, and is 200 or fewer characters long.
    //Postconditions: The function will read the digits of the
    //	large integer character by character, 
    //	convert them into integers and return a 
    //             pointer to the appropriate struct integer.
    struct integer* read_integer(char* stringInt);
    
    //Preconditions: p is a pointer to a big integer.
    //Postconditions: The big integer pointed to by p is 
    //                printed out.
    void print(struct integer *p);
    
    //Preconditions: p and q are pointers to struct integers.
    //Postconditions: A new struct integer is created that 
    //                stores the sum of the integers pointed to 
    //                by p and q and a pointer to it is 
    //                returned.
    struct integer* add(struct integer *p, struct integer *q);
    
    //Preconditions: p and q are pointers to struct integers.
    //Postconditions: A new struct integer is created that 
    //                stores the absolute value of the 
    //                difference between the two and a pointer 
    //                to this is returned.
    struct integer* subtract(struct integer *p, struct integer *q);
    
    //Preconditions: Both parameters of the function are 
    //	  pointers to struct integer. 
    //Postconditions: The function compares the digits of two 
    //	numbers and returns: 
    //    -1 if the first number is smaller than the second, 
    //     0 if the first number is equal to the second number,
    //   1 if the first number is greater than the second.  
    int compare(struct integer *p, struct integer *q);
    ...Yeah, I've got a lot of work to do. This is what happens when you don't read ALL of the instructions... >_<

  8. #68
    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by Graham Aker View Post
    ...Uh, what? That's a bit vague...
    No that is actually remarkably explicit. You pass the address of the specific object (that you want to store the number in) to the function.

  9. #69
    Confused College Student Graham Aker's Avatar
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    Oh, durr. Now I feel like a complete idiot. >_<;;

  10. #70
    In my head happyclown's Avatar
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    Quote Originally Posted by Graham Aker View Post
    Oh, durr. Now I feel like a complete idiot. >_<;;
    Don't worry about it.

    Have you got a headache yet? Maybe you should take a short break from it all.
    OS: Linux Mint 13(Maya) LTS 64 bit.

  11. #71
    Confused College Student Graham Aker's Avatar
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    Okay, so does anyone have any idea how I can take a string and turn it into an integer array with a function that's header is "struct integer* read_integer(char* stringInt);"?

  12. #72
    Confused College Student Graham Aker's Avatar
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    Quote Originally Posted by happyclown View Post
    Don't worry about it.

    Have you got a headache yet? Maybe you should take a short break from it all.
    I wish I could, honestly, but it's due tomorrow at midnight and I've got a three-part Java project due wednesday at midnight as well.

    Here's hoping the Java project's easier than this. o_o;;

  13. #73
    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by Graham Aker View Post
    Okay, so does anyone have any idea how I can take a string and turn it into an integer array with a function that's header is "struct integer* read_integer(char* stringInt);"?
    Given that you've had that all along, I would say "you". (You just have to return the integer object, or rather its address, instead of passing it in.)

  14. #74
    Confused College Student Graham Aker's Avatar
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    Quote Originally Posted by tabstop View Post
    Given that you've had that all along, I would say "you". (You just have to return the integer object, or rather its address, instead of passing it in.)
    Seriously? That's it?
    ...Please excuse me while I bang my head against this desk here.

    ...No, wait, hold that thought, it's crashing when I try it. Though I'm sure I'm doing it horribly wrong...

    here's what I tried. Feel free to tell me how much I screwed it up:
    Code:
    struct integer* read_integer(char* stringInt){
          int arraysize = strlen(stringInt);      
          int intarray[big];
          
    //Move the integer into the array      
          for(i=arraysize, j=0; i>-1; i--){
               if(isdigit(stringInt[i])){
                    intarray[i]=stringInt[i] - '0';
               }
          }
          return intarray[i];
    };

  15. #75
    CSharpener vart's Avatar
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    horribble code
    what you store in your intarray if the char is not a digit?
    you return value of the int that is not initialized
    you loose all you work - because the inarray is a local var that is detroyed after the function ends
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

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