array search

[wallyzwurld]

hello,

i've been working in c for a few months now, but am relatively new to the concept of arrays. the program that i am working on requires me to read in a string of up to 20 unique characters into an array, and then call a function to read the string, identify the unique characters, and print the characters out on a single line with no white spaces.

that being said my question is how to read through the array (without using a string) and determine which characters are unique, and which have already been used.

i hope this makes sense, and i appreciate any help i can get.

thanks a lot!

[Banfa]

Try this eaxmple

#include <stdio.h>
#include <string.h>
 
int main(int argc, char** argp)
{
    char Text[] = "Hello World";
    size_t ix;
 
    for(ix=0; ix<strlen(Text); ix++)
    {
        char c = Text[ix];
        putchar(c);
    }
 
    putchar('\n');
}
 

[wallyzwurld]

Try this eaxmple

#include <stdio.h>
#include <string.h>
 
int main(int argc, char** argp)
{
    char Text[] = "Hello World";
    size_t ix;
 
    for(ix=0; ix<strlen(Text); ix++)
    {
        char c = Text[ix];
        putchar(c);
    }
 
    putchar('\n');
}
 

yeah but that is using the string library, is it not? it makes sense to me that way, but i'm supposed to try to write it w/o using the string... any ideas on that? that's what is throwing me.

[Banfa]

the only bit of that that uses the string library is strlen, if you really want to that can easily be re-written as

size_t myStrLen(const char *pString)
{
    size_t len = 0;
 
    while(*pString++)
    {
        len++;
    }
 
    return len;
}
 

You can similarly re-write all the string library functions, they are all fairly basic.