Math + CS = 11

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…

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

#include <stdio.h>
 
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!