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  1. #include <stdio.h>
  2.  
  3. // 1. String Length (Exercise 8.30)
  4. size_t my_strlen_arr(const char *s) {
  5.     size_t i = 0;
  6.     while (s[i] != '\0') i++;
  7.     return i;
  8. }
  9. size_t my_strlen_ptr(const char *s) {
  10.     size_t len = 0;
  11.     while (*s++) len++;
  12.     return len;
  13. }
  14.  
  15. // 2. String Copy (Exercise 8.28)
  16. void my_strcpy_arr(char *s1, const char *s2) {
  17.     int i = 0;
  18.     while ((s1[i] = s2[i]) != '\0') i++;
  19. }
  20. void my_strcpy_ptr(char *s1, const char *s2) {
  21.     while ((*s1++ = *s2++));
  22. }
  23.  
  24. // 3. String Compare (Exercise 8.29)
  25. int my_strcmp_arr(const char *s1, const char *s2) {
  26.     int i = 0;
  27.     while (s1[i] == s2[i] && s1[i] != '\0') i++;
  28.     return s1[i] - s2[i];
  29. }
  30. int my_strcmp_ptr(const char *s1, const char *s2) {
  31.     while (*s1 == *s2 && *s1 != '\0') {
  32.         s1++; s2++;
  33.     }
  34.     return *s1 - *s2;
  35. }
  36.  
  37. int main(void) {
  38.     char str1[50];
  39.     char str2[] = "Hello";
  40.     char str3[] = "World";
  41.  
  42.     my_strcpy_ptr(str1, str2);
  43.     printf("Copied string: %s\n", str1);
  44.     printf("Length of string: %zu\n", my_strlen_arr(str1));
  45.     printf("Comparison result: %d\n", my_strcmp_ptr(str2, str3));
  46.  
  47.     return 0;
  48. }
Success #stdin #stdout 0s 5316KB
comments (?)
stdin 
Standard input is empty
stdout 
Copied string: Hello
Length of string: 5
Comparison result: -15
https://ideone.com/3KXHuR
language:
C (gcc 8.3)
created:
2 days ago
visibility:
public

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