university/S1/GdCP/klausur_uebung/strmatch.c

#include<string.h>
#include<ctype.h>

int str_match(const char s[], const char p[], int strict) {
  // takes string and pattern and strict flag
  // should return if the characters in the pattern appear in the string in the same order
  // strict should also check for difference in capital letters
  // it does not matter whether there are characters in between (other)
  
  int ls = strlen(s);
  int lp = strlen(p);
  int o = -1;

  // Loop the patterns and the string for each pattern
  for (const char *cp = p; *p != '\0'; p++) { 
    for (int j = 0; j < ls; j++) {
      char chp = *p;
      char cha = s[j];

      if (!strict) {
        chp = (char) tolower(chp); cha = (char) tolower(cha);
      }
      if (cha == chp) {
        // Break condition
        if (j < o) {
          return 0;
        } 

        // Set the new occurence
        o = j;
        break;
      }
    }
  }
  return 1;
}

#include<stdio.h>

int main() {
  printf("%d\n", str_match("Hallo Welt", "alo", 1));
  printf("%d\n", str_match("Hallo Welt", "alo", 0));
  printf("%d\n", str_match("Hallo Welt", "alho", 1));
  printf("%d\n", str_match("Hallo Welt", "alho", 0));
}