squeeze.c

#include<assert.h>
#include<stdio.h>
#include<string.h>

/* The function squeeze removes all instances of specified characters
from the input string array. The characters to be excluded are given in
a second argument.*/

struct testrec {
  char inpu[30];
  char *exclude;
  char *expect;
};

struct testrec t0 = {"abcabcabc", "a", "bcbcbc"};
struct testrec t1 = {"abcabcabc", "b", "acacac"};
struct testrec t2 = {"abcabcabc", "c", "ababab"};
struct testrec t3 = {"abcabcabc", "ab", "ccc"};
struct testrec t4 = {"abcabcabc", "cb", "aaa"};
struct testrec t5 = {"abcabcabc", "cba", ""};
struct testrec t6 = {"abcabcabc", "", "abcabcabc"};
struct testrec t7 = {"abcabcabc", "xyz", "abcabcabc"};
struct testrec t8 = {"abcabcabc", "bbbbb", "acacac"};
struct testrec t9 = {"abcabcabc", "abcabcabc", ""};
struct testrec t10 = {"", "abc", ""};
struct testrec t11 = {"", "", ""};

int
within(char ch, const char cset[]) {
  int i;

  i = 0;
  while (cset[i] != '\0' && cset[i] != ch) {
    i++;
  }
  assert (cset[i] == '\0' || cset[i] == ch);
  return (cset[i] != '\0');  /* IS within */
}

void
squeeze(char s[], const char exclude[]) {
  int i,j;
  
  i = j = 0;
  while (s[i] != '\0') {
    if (within(s[i], exclude))
      i++;    /* skip */
    else
      s[j++] = s[i++];
  }
  s[j] = '\0';
}

void
utest (struct testrec *tc) {
  char buf[256];
  strcpy(buf, tc->inpu);
  squeeze(buf, tc->exclude);
  assert(strcmp(buf, tc->expect) == 0);
  printf("PASS\n");
}

int
main (int argc, char *argv[]) {
  utest(&t0);
  utest(&t1);
  utest(&t2);
  utest(&t3);
  utest(&t4);
  utest(&t5);
  utest(&t6);
  utest(&t7);
  utest(&t8);
  utest(&t9);
  utest(&t10);
  utest(&t11);
  return 0;
}