Question

I am using this function:

int times_on_table(char *search,struct table index[],int wct){
 int ct=0,num=0;
 while(ct<wct){
     if(strcmp(search,(index[ct].label))==0) {
         num++;
     }
     ct++;
 }
 return num;
}

to search through an array of structs and find all the times a certain string is stored in the array and returns the number of times the string occurs. Whenever i use this function inside main:

/*EDIT: i had a main from the wrong program my apologies*/

int main(int argc, char **argv){
    int numwds=get_num_words(argv[1]);
    struct table index[numwds];

    int a;
    struct cmd_ops symbol[22];
    store(argv[1],index,numwds);
    ops_gen(symbol);
    int b=times_on_table("in",index,numwds);
    printf("%d",b);
}

the code works fine. However, when i try to use it inside certain functions like this one

struct table* store(char *filename,struct table index[]) {
    FILE *fp;
    fp=fopen(filename,"r");
    char *a;int d=0,e=0,t=0;
    a=malloc(60);
    int wordcount=get_num_words(filename);
    while(d<wordcount){
        fscanf(fp,"%s",a);
        if ((index[d].label=strdup(a))==NULL)
            break;
        index[d].word_num=d;

        times_on_table("this",index,wordcount);/*when i comment this out
                                                 of my code it runs fine*/

        index[d].address=findline(filename,index[d].label,wordcount,index,t);
        d++;
    }
    free(a);
}

the code does not run and gives me a segmentation fault. Any thoughts?

EDIT: I don’t know if this helps but when i get the segfault, it happens before even the first line of code in main is executed.

EDIT:here is the other function that causes a segfault when times_on_table() is called:

int findline(char *filename,char *check,int wordcount,struct table index[],int t){
char *a;
a=malloc(60);
int b=line_count(filename);
int ch;
fpos_t pos;

int line=0,wd=0,loc,s=0,c=1,times;

times=times_on_table(check,index,wordcount);

FILE *fp;
fp=fopen(filename,"r");

int list[wordcount];

while(c<=b){
    fscanf(fp,"%s",a);
    fgetpos(fp,&pos);

    ch=fgetc(fp);ch=fgetc(fp);

    if(strcmp(a,check)==0){
       if(times==0)
            return line;
       else
            times--;
    }

    if(ch==10){
        line++;c++;
    }
    else
        fsetpos(fp,&pos);
    }
    return line;
 }

it was in this function that i first added times_on_table(), and had the segmentation fault keep my program from running.

Answer 1

Here

while(d<wordcount){
    fscanf(fp,"%s",a);
    if ((index[d].label=strdup(a))==NULL)
        break;
    index[d].word_num=d;

    times_on_table("this",index,wordcount);

you try to count the occurrences of "this" in a wordcount long array, but you have only filled d+1 slots of the array. The other slots may contain garbage, and then accessing index[ct].label is likely to cause a segmentation fault when ct > d.