Question

I’m writing a little program in C, for check the HTML file have the right open and close tags?
but i’ve got some issues…
i have a file what contains the all possible tags, named tags.txt(those are only the first ones):

<a>
</a>
<abbr>
</abbr>
<area>
</area>
<aside>
</aside>

and i have the htmlfile.html, what I have to check:

<!--#echo var="date" -->
<area>
</area>
<area>
</area>

secondly, i want to replace the comments like this to the sysdate
like , the format is OK i can do it, but the prog puts in the file
this

my code:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#define MAX_SIZE 512


void menu();
void check();
void datumos();


int main(int argc,char *argv[])
{
    menu();

    return 0;
}

void menu()
{
    char menu[MAX_SIZE];
    while(1 < 2)
    {
            printf("\npress a button:\n\n");

                    printf("\tFile HTML check..............:c\n");
                    printf("\t<!--#echo var="date" -->...........:d\n");
                    printf("\tExit:\tCTRL + C\n");
                    scanf("%s",menu);

            if( strcmp(menu,"c") == 0 )
            {
                    check();
            }
            else if( strcmp(menu,"d") == 0 )
            {
                    datumos();
            }

    }
}

void check()
{
    FILE *htmlfile;
    FILE *checkfile;

    htmlfile = fopen("htmlfile.html","w");
    checkfile = fopen("tags.txt","r");

char line[MAX_SIZE];
char htmlline[MAX_SIZE];
char tags[189][30];


int i=0;

printf("\tcheck__1\n");

while(fgets(line,sizeof(line),checkfile) != NULL)
    {

        int j;
    for(j=0; j<sizeof(line); ++j)
    {
        tags[i][j]=line[j];
    }
    ++i;

    }
printf("\tcheck__2\n");


int k=0;    char htmlfiletags[MAX_SIZE][30];
    while(fgets(htmlline,sizeof(htmlline),htmlfile) != NULL)
    {
    char currentline[sizeof(htmlline)];
    int j=0;

        if( currentline[j]=="<" )
        {

                while(currentline[j]!=">") 
                {
                    htmlfiletags[k][j]=currentline[j];
                    ++j;
                }
                strcat(htmlfiletags[k][j+1],">"); 
                ++k; 
        }
}
printf("\tcheck__3\n");


 int n;
 for(n=0; n<sizeof(htmlfiletags); ++n)
 {
     int j; int howmanytimesnot=0;

     for(j=0; j<sizeof(tags); ++j)
     {
         printf("\tcheck__3/1\n");


         if(strcmp(htmlfiletags[n],tags[j])==0)
         {
             printf("\t%d\n", howmanytimesnot);

             ++howmanytimesnot;
         }
     }

    printf("\tcheck__3/3\n");

     if(!(howmanytimesnot<sizeof(tags)))
        {
            printf("\tcheck__3/4\n");
          printf("the file is not wellformed");

          exit (1);
        }

 }
 printf("\tcheck__4\n");


}

void copy_file(const char *from,const char *to)
{
    FILE *fr;
    FILE *t;
    fr = fopen(from,"r");
    t = fopen(to,"w");

    char line[MAX_SIZE];

    char row[MAX_SIZE];

    while(fgets(line,sizeof(line),fr) != NULL)
    {
            sscanf(line,"%s",row);
            fprintf(t,"%s\n",row);
    }

    fclose(fr);
    fclose(t);

    remove("tempfile.html");
 }


void datumos()
{
time_t now = time(NULL);
struct tm *t = localtime(&now);
char date_time[30];
strftime( date_time, sizeof(date_time), "%x_%X", t );

FILE *htmlfile;
    FILE *tempfile;
    htmlfile = fopen("htmlfile.html","r");
    tempfile = fopen("tempfile.html","w");
    char line[MAX_SIZE];
    //char datecomment[]="<!--#echo var=date -->";

    while(fgets(line,sizeof(line),htmlfile) != NULL)
    {

            if( strcmp(line,"<!--#echo var="date" -->") == 0 )
            {

            char row[40];
            strcpy(row,"<!--");
            strcat(row, date_time);
            strcat(row,"-->");

    printf("%s",row);
            fputs(row,tempfile);

            }
            else
            {
                    fputs(line,tempfile);
            }
    }

    fclose(htmlfile);
    fclose(tempfile);

    copy_file("tempfile.html","htmlfile.html");

}

it dies in this, in the inner for loop, in the if at the 200th check… i dont know why…

 int n;
 for(n=0; n<sizeof(htmlfiletags); ++n)
 {
     int j; int howmanytimesnot=0;

     for(j=0; j<sizeof(tags); ++j)
     {
         printf("\tcheck__3/1\n");


         if(strcmp(htmlfiletags[n],tags[j])==0)
         {
             printf("\t%d\n", howmanytimesnot);

             ++howmanytimesnot;
         }
     }

    printf("\tcheck__3/3\n");

     if(!(howmanytimesnot<sizeof(tags)))
        {
            printf("\tcheck__3/4\n");
          printf("the file is not wellformed");

          exit (1);
        }

 }

Thanks for all reply!!
G

Answer 1

Your code is very complicated, it has several issues.

Here’s one:

for(j=0; j<sizeof(tags); ++j)

this will not do what I believe you expect; sizeof(tags) is not the array length of tags (which is declared as char tags[189][30];), it’s the total size of the variable. So, this loop will go from 0 to 189 * 30 – 1, i.e. 5669, and thus index way out beyond the end of array.

Also, the idea to use sizeof here in any way is wrong, since the content of tags comes from a file and it thus impossible for the compiler to know. Remember that sizeof is evaluated at compile-time, for expressions like these.

You need to have a variable (e.g. size_t num_tags) that you increment for each line parsed from the tags file, and that you later use to iterate over tags.