It's My String…

admin — Thu, 18 Jun 2009 09:44:16 +0000

Okay, I just had way too much fun writing this so I thought I’d post it. It’s exercise 4-1 in K&R2. It’s pretty much “write a function which returns the rightmost index of some character in some string.”

#include 
#include 
 
int strindex(char s[], int t);
 
char mystring[] = "This is my string and I can cry if I want to.";
 
main()
{
    int mychar = 'z';
    printf("%c is at %d in %s\n", mychar, strindex(mystring, mychar), mystring);
}
 
int strindex(char s[], int t)
{
    int i;
    for(i = strlen(s)-1; i >= 0; i--) {
        if(t == s[i])
            return i;
    }
    return -1;
}

On a somewhat more serious note, I have finally bought some new shoes (yay?) from Zappos.com. They’re orange and like all orange things, they are good. Geoff’s Theorem: If something is orange, then it is good.

Another cool thing that every Mac user should play around with is Delicious Library 2. If you have never heard of it, think of it as a digital book shelf where you can display books, movies, video games, electronics, ect. that you own. The best part is that it lets you use your iSight camera to scan in the bar codes for everything! I got it as part of the Macheist bundle and have never played with it until now and I gotta tell you, scanning everything in is way more fun than it should be.

C

admin — Wed, 17 Jun 2009 06:47:21 +0000

I’ve decided that I want to learn C instead of Haskell and Python now and am using the book to learn from. I gotta say, I’m very impressed with K&R2. Absolutely great. The best part about the book is that it contains many exercises at the end of each section which gives you practice writing C programs. I just finished the 2-4 exercises and it was quite a challenge for some reason. The problem was to write a function that takes two strings and remembers the characters in one string from the other. I thought it’s worth posting my solution. I’m not sure how ‘good’ my style is, but I’m following my style from K&R so it can’t be very bad…

#include 
 
void squeeze(char[], char[]);
 
main()
{
    char s1[] = "Hello, world!";
    char s2[] = "Hlo";
    squeeze(s1, s2);
    printf("%s\n", s1);
}
 
/* squeeze: deletes all characters in s2 from s1 */
void squeeze(char s1[], char s2[])
{
    int i, j, k;
    for(i = j = 0; s1[i] != '\0'; i++) {
        int found = 0;
        for(k = 0; s2[k] != '\0'; k++) {
            if(s1[i] == s2[k]) {
                found = 1;
            }
        }
        if(!found) {
            s1[j++] = s1[i];
        }
    }
    s1[j] = '\0';
}

The stuff in the main is just some testing that I did. From what I can tell, it seems to work as expected. Yay C!

Math + CS = 11 » K&R2

It's My String…

C