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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4.  
  5. #define MAX_WORDS 10
  6.  
  7. #define TEST(s) { \
  8.     char *str = make_string(s); \
  9.     puts(str); \
  10.     free(str); \
  11. }
  12.  
  13. static size_t words_count = 0;
  14. static const char *words[MAX_WORDS] = { 0 };
  15.  
  16. int cmp_str(const void *p1, const void *p2)
  17. { return strlen(*(const char **) p1) < strlen(*(const char **) p2); }
  18.  
  19. void add_word(const char *word)
  20. {
  21.     if (words_count < MAX_WORDS)
  22.         words[words_count++] = word;
  23.     else {
  24.         puts("error: too much words!");
  25.         exit(1);
  26.     }
  27. }
  28.  
  29. char *get_word(char *str)
  30. {
  31.     char *ret;
  32.  
  33.     if (str == NULL || *str == 0)
  34.         return NULL;
  35.  
  36.     while (*str && !isalpha(*str))
  37.         ++str;
  38.  
  39.     ret = str;
  40.  
  41.     while (*str && isalpha(*str))
  42.         ++str;
  43.     *str = 0;
  44.  
  45.     return *ret ? ret : NULL;
  46. }
  47.  
  48. char *make_string(const char *source_str)
  49. {
  50.     size_t i;
  51.     char *ret;
  52.     char *word;
  53.     char *str;
  54.  
  55.     words_count = 0;
  56.     str = alloca(strlen(source_str) + 2);
  57.     strcpy(str, source_str);
  58.     str[strlen(source_str) + 1] = 0;
  59.  
  60.     while ((word = get_word(str)) != NULL) {
  61.         add_word(word);
  62.         str = word + strlen(word) + 1;
  63.     }
  64.  
  65.     qsort(words, words_count, sizeof(char *), cmp_str);
  66.  
  67.     ret = calloc(strlen(source_str) + 1, 1);
  68.     for (i = 0; i < words_count; i++) {
  69.         strcat(ret, words[i]);
  70.  
  71.         if (i != words_count - 1)
  72.             strcat(ret, " ");
  73.     }
  74.  
  75.     return ret;
  76. }
  77.  
  78. int main()
  79. {
  80.     TEST("hello");
  81.     TEST(" hell, world ");
  82.     TEST("      my other    car is cdr   ");
  83.     TEST("  the quick   brown fox,  jumps over  the, lazy dog   ");
  84.     return 0;
  85. }
  86.  
Success #stdin #stdout 0.01s 1808KB
comments (?)
stdin 
Standard input is empty
stdout 
hello
world hell
other car cdr my is
quick brown jumps over lazy the fox the dog
https://ideone.com/gtY5EF
language:
C (gcc 8.3)
created:
13 years ago
visibility:
public

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