Thread: help understanding arrays of strings!

Originally Posted by vart

also it is a good practice to put with the array - the array length as a second parameter
in this case your printStrings function does not need to know that arrays are declared with STRING_COUNT constant

also when fgets returns null it could be not due to error but due to EOF condition, so maybe user just does not want to enter all 5 srings and will stop after 3 (he can emulate EOF pressing Ctrl+Z if I remember)
so in this case you also may want to proceed the actual number of received strings, and not the preallocated number - so passing the number of filled array members will also help to solve this problem

hi!
these are very important considerations so I tried to put them together in this other small program which shows and counts the strings which terminate by a key string entered by the user.
The problem is that i cannot catch the EOF condition properly (this is the reason why i entered the blank line request): if i press CTRL+Z i get just a "stopped" message and the program gets terminated... so the while cicle in my readlines() never fails (and i have to check in the block for blank lines!)
do you have any hints? is it possible to declare the key string in a more elegant way than the way i did? thanks again!

Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXLINES 5
#define MAX_STRLEN 256

int readlines (char * lines[], int maxlines);
int countlines (char * lines[], int numlines, char * key,int keyDim);
void writelines (char * lines[],int numlines);

int main()
{
	char *lines[MAXLINES], *key[1];
	printf("Insert text. Leave a blank line when you're finished\n");
	fflush(stdout);
	int numl;

	if ((numl=readlines(lines,MAXLINES))<0) 
	{
		exit(1);
	}

	printf("Enter your key string\n");
	fflush(stdout);

	if (readlines(key,1)<0)
	{
		exit(1);
	}

	printf("Your entered lines (%d total):\n",numl); 
	writelines(lines,numl);
	printf("Your key:\n");
	writelines(key,1);
	printf("String(s) which terminate by your key:\n");
	printf("I found %d such line(s)\n",countlines (lines,numl,key[0],strlen(key[0])));
}


int readlines (char * lines[],int maxlines)
{
	char buffer[MAX_STRLEN];
	int line=1;
	while ( fgets(buffer,MAX_STRLEN,stdin) ) 
	{
		if (strlen(buffer)==1) return line-1;

		buffer[strlen(buffer)-1]='\0';
		if (! (lines[line-1]=malloc(strlen(buffer)+1)) )
		{
			printf("Out of memory\n");
			return -1;
		}
		strcpy(lines[line-1],buffer);
		
		if (line==maxlines) return line;

		line++;
		
	}
	return line-1;
}

int countlines (char * lines[], int numlines, char * key,int keyDim)
{
	int i,count=0;
	for(i=0;i<numlines;i++)
	{
		if ( strstr((lines[i]+(strlen(lines[i])-keyDim)),key) ) {
		count++;
		puts(lines[i]);
		}
	}
	return count;
}

void writelines (char * lines[],int numlines)
{
	int i;
	for (i=0;i<numlines;i++) 
	{
		puts(lines[i]);
	}
}