Character Arrays in C

[raddmadd]

I understand simple character arrays; however I do not understand this code example in the K & R book:



#include <stdio.h>
#define MAXLINE 1000 /* maximum input line length */

int getline(char line[], int maxline);
void copy(char to[], char from[]);

/* print the longest input line */
main()
{
int len; /* current line length */
int max; /* maximum length seen so far */
char line[MAXLINE]; /* current input line */
char longest[MAXLINE]; /* longest line saved here */
max = 0;
while ((len = getline(line, MAXLINE)) > 0)
if (len > max) {
max = len;
copy(longest, line);
}
if (max > 0) /* there was a line */
printf("%s", longest);
return 0;
}

/* getline: read a line into s, return length */
int getline(char s[],int lim)
{
int c, i;
for (i=0; i < lim-1 && (c=getchar())!=EOF && c!='\n'; ++i)
s[i] = c;
if (c == '\n') {
s[i] = c;
++i;
}
s[i] = '\0';
return i;
}

/* copy: copy 'from' into 'to'; assume to is big enough */
void copy(char to[], char from[])
{
int i;
i = 0;
while ((to[i] = from[i]) != '\0')
++i;
}


As the comment before main says, the program outputs the longest string. However, a few things I don't understand.

When I declare an array, I cannot leave the array subscript empty (int blah[]) I have to specify the subscript. However in this program, the parameters for getline and copy have arrays with an empty subscript. I don't understand this and I don't understand using the array line and longest. They are being used as arguments without specifying which subscript is being used.

I may not be clear on what I do not understand, but I would like someone to explain how line and longest are being passed to the functions.

Thank you in advance.

[LaRoza]

I think you haven't gotten to the part where the relationships between arrays and pointers is explained.

The program you posted makes use of that fact, and an array name is a pointer.