1 /* Makes a lexicographical comparison between the first n */ 2 /* numbers of two given strings */ 3 /* similar to strncmp() function from <string.h> */ 4 5 #include <stdio.h> 6 #include <string.h> 7 8 /* This function calculates the length of given string 9 and returns it by its name, equivalent to strlen() 10 function from <string.h> library */ 11 size_t str_len(const char *str) 12 { 13 size_t i; 14 15 if(!str) return 1; 16 17 for(i = 0; str[i]; i++); 18 19 return i; 20 } 21 22 /* This function is equivalent to strncmp() function from 23 <string.h> library */ 24 int str_cmp(const char *sa, const char *sb, size_t n) 25 { 26 /* Since the return value is an integer this function won't check for errors */ 27 int cmp; 28 size_t i; 29 30 for(i = cmp = 0; (i < n) && sa[i] && sb[i]; i++) 31 cmp += sa[i] - sb[i]; 32 33 return cmp; 34 } 35 36 37 int main(void) { 38 39 char s1[] = "HELLO"; 40 char s2[] = "hello"; 41 42 int i, j; 43 i = str_cmp(s1, s2, 109); 44 j = strncmp(s1, s2, 8); 45 46 printf("%d\n%d\n", i, j); 47 return 0; 48 }
