Question

I am attempting to read a file with some random names in the format “ADAM”,”MARK”,”JESSIE” …..

I have some constraints, the file should be read in a function but should be accessible form the main function with no global variables.
The file size and the no of names in the file are not known.
This is what I have done till now. I have some difficulty with dynamic 2d array as I have not used them much.

/* Function to read from the file */
int read_names(FILE *input, char ***names, int *name_count)
{
    int f1,size,count,i,j=0;
    char **name_array,*text,pos=0;
    /* get the file size */
    f1=open("names.txt",O_RDONLY);
    size=lseek(f1,0,SEEK_END);
    close(f1);
    /* Reading all the characters of the file into memory */
    //Since file size is known we can use block transfer
    text=(char *) malloc(size * sizeof(char) );
    fscanf(input,"%s",text);

    /* Finding the no of names in the file */
    for(i=0;i<size;i++)
    {
        if(text[i]==',')
            count++;
    }
    printf("No. of names determined\n");

    /* Assigning the Name count to the pointer */
    name_count=(int*)malloc(sizeof(int));
    *name_count=count;


    name_array=(char **) malloc(count * sizeof(char *));
    for(i=0;i<count;i++)
    {
        name_array[i]=(char*) malloc(10 *sizeof(char ));
    }
    for(i=0;i<size;i++)
    {
        if(text[i]!='"')
            if(text[i]==',')
            {
                **name_array[pos][j]='\0'; //error here
                pos++;
                j=0;
            }
            else
                name_array[pos][j++]=text[i];
    }
    printf("Names Counted\n");
    printf("Total no of names: %d\n",*name_count);
    names=(char ***) malloc(sizeof(char **);
    names=&name_array;
    return 1;
}

/* Main Function */
int main(int argc, char *argv[])
{
    FILE *fp;
    char ***names;
    int *name_count;
    int status;
    // Opening the file
    fp = fopen("names.txt","r");
    // Now read from file
    status = read_names(fp,names,name_count);
    printf("From Main\n");
    fclose(fp);
    system("PAUSE");
    return 0;
}

I use WxDev and am getting an error “invalid type argument of `unary *’ when I try to assign the null character.

Any pointers on how to do this?

Answer 1

            **name_array[pos][j]='\0'; \\error here

I see that name_array is declared as

char **name_array

Problem is that

**name_array[pos][j] tries to dereference (twice!!) a character

**   (name_array[pos]) [j];    /* name_array[pos] is of type (char*) */
** ( (name_array[pos]) [j] );  /* name_array[pos][j] is of type (char) */

You cannot dereference a character.

Suggestion: simplify your code.
When code doesn’t “behave”, it usually is not because it is too simple 😉