fgetc,getc causes the program to crash when reading from text file

Question

Whats wrong? I'm pretty sure my syntax is correct since it has no warnings. Plus it won't go past getc(document); I tried fgetc(document); same result. What am I not getting here? (I used printf("$"); to see where it crashes)

char temp[51];
int cntr = 0,listcntr = 0,buffer;
FILE *document;
contact list[MAXCONTACTS];
document = fopen("addressbook.txt","r");
do
{
    for(cntr = 0;cntr < 51; cntr++)
        temp[cntr] = '\0';
    cntr = 0;
    do
    {

        buffer = getc(document);
         printf("$");
        if(buffer != '\t')
            temp[cntr] = buffer;
        ++cntr; 
    }while(buffer != '\t'&& buffer != EOF);
list[listcntr].name = temp;

What language are you using? The way you declare document seems really strange to me — Ivan Koblik, Sep 12 '12 at 09:51
Is this: `document = ("addressbook.txt","r");` valid? Seems like you are missing `fopen` — Bart Friederichs, Sep 12 '12 at 09:52
I would suggest you debug and watch cntr to check if it does not exceed 51 by chance. If that is not possible add debug printing statement for its value. — Ivaylo Strandjev, Sep 12 '12 at 09:53
Could you post full snippet what you have here is not syntactically correct. For example there is an extra `do{` — Ivan Koblik, Sep 12 '12 at 09:59
@Ivan: exactly. It doesn't even compile so it can never crash. — wildplasser, Sep 12 '12 at 10:02
@wildplasser its just a snippet. Didn't include header files and the other functions, I thought people here hated walls of code — jantristanmilan, Sep 12 '12 at 10:05
people here dislike walls of code, just as they dislike code that doesn't compile. Just remove everything that is not required to reproduce the error. Leave the rest of the code in a condition it compiles. Also add information about the kind of crash, and potentially a stacktrace. — moooeeeep, Sep 12 '12 at 10:07
It is not a snippet, it is incomplete code. The first `do {` *could* end in a `} while (c=fgetc(stdin);` or whatever. The missing part of the block could do *anything*, including `memset(temp, 42, 1333);`. — wildplasser, Sep 12 '12 at 10:09
have you made sure the output is flushed as you expect it to be flushed? change to `printf("this never happens\n");` (mind the newline character) — moooeeeep, Sep 12 '12 at 10:10
yeah, I'm pretty sure its there. Cause in the main fuction I made it check if fopen("addressbook.txt","r") == NULL — jantristanmilan, Sep 12 '12 at 09:57

Ivan Koblik · Accepted Answer · 2012-09-12T10:06:55.733

OK I modified your code a little and added a couple of checks, maybe it will be enough.

char temp[51];
int listcntr = 0,buffer;
contact list[MAXCONTACTS];
FILE *document = fopen("addressbook.txt","r");

if (NULL == document){
    //exit here
}

for(int i = 0;i < 51; i++){
    temp[i] = '\0';
}

int cntr = 0;
for (int cntr=0; cntr < 51 && !feof(document); cntr++){
    buffer = getc(document);
    if (buffer == '\t'){
        break;
    }
    temp[cntr] = buffer;
}

if(listcntr < MAXCONTACTS){
    // you should probably copy temp here
    list[listcntr].name = temp;
}

fgetc,getc causes the program to crash when reading from text file

1 Answers1