Написать программу, содержащую две функции, сравнения строк, эквивалентные стандартной функции strcmp

#include <stdio.h>
#include <string.h>
 
//ptr
int p_strcmp(const char* s1, const char* s2){
    int ret;
    while(!(ret = (int)*s1 - *s2) && *s1){
        ++s1;
        ++s2;
    }
    return ret;
}
 
//index
int i_strcmp(const char* s1, const char* s2){
    int ret, i = 0, j = 0;
    while(!(ret = (int)*(s1 + i) - *(s2 + j)) && *(s1 + i)){
        ++i;
        ++j;
    }
    return ret;
}
 
int main(void){
    printf("% 2d\t% 2d\n", strcmp("ABC", "ABC"), p_strcmp("ABC", "ABC"));
    printf("% 2d\t% 2d\n", strcmp("A",  "ABC"),  p_strcmp("A", "ABC"));
    printf("% 2d\t% 2d\n", strcmp("ABC", "AB"),  p_strcmp("ABC", "AB"));
    putchar('\n');
    printf("% 2d\t% 2d\n", strcmp("xyz", "XYZ"),  i_strcmp("xyz", "XYZ"));
    printf("% 2d\t% 2d\n", strcmp("PHP", "PHPi"), i_strcmp("PHP", "PHPi"));
    printf("% 2d\t% 2d\n", strcmp("12",  "19"),   i_strcmp("12", "19"));
    return 0;
}

#include <stdio.h>
 
int mystrcmp(const char * a, const char * b) {
    return ( *a && *a == *b ) ? mystrcmp(a + 1, b + 1) : *a - *b;
}
 
int main(void) {
    char sA[BUFSIZ], sB[BUFSIZ];
    
    while ( printf("First: ") && fgets(sA, BUFSIZ, stdin) && *sA != '\n' && printf("Second: ") && fgets(sB, BUFSIZ, stdin) ) {
        int d = mystrcmp(sA, sB);
        printf("%s\n", ( d < 0 ) ? "First less" : ( d > 0 ) ? "Second less" : "The same");
    }
    
    return 0;
}

#include <stdio.h> 
#include <stdlib.h> 
 
int ind(char *x, char *y)
{
    int i, result;
    for (i = 0, result = 0; ; i++)
    {
        if ((x[i] == 0) && (y[i] == 0)) { break; }
        if (x[i] == 0) { result = 1; break; }
        if (y[i] == 0) { result = 2; break; }
        if (x[i]<y[i]) { result = 1; break; }
        else if (x[i]>y[i]) { result = 2; break; }
    }
    return result;
}
 
int ukaz(char *x, char *y)
{
    int i, result;
    for (i = 0, result = 0; ; i++)
    {
        if ((*(x + i) == 0) && (*(y + i) == 0)) { break; }
        if (*(x + i) == 0) { result = 1; break; }
        if (*(y + i) == 0) { result = 2; break; }
        if (*(x + i)<*(y + i)) { result = 1; break; }
        else if (*(x + i)>*(y + i)) { result = 2; break; }
    }
    return result;
}
 
int main() {
    char a[100], b[100];
    int status;
    printf("A="); scanf("%s", a);
    printf("B="); scanf("%s", b);
    status = ind(a, b);
    switch (status)
    {
    case 0: printf("With ind:\nA=B"); break;
    case 1: printf("With ind:\nA<B"); break;
    case 2: printf("With ind:\nA>B"); break;
    }
    printf("\n");
    status = ukaz(a, b);
    switch (status)
    {
    case 0: printf("With ukaz:\nA=B\n"); break;
    case 1: printf("With ukaz:\nA<B\n"); break;
    case 2: printf("With ukaz:\nA>B\n"); break;
    }
}

#include <stdio.h>
#include <string.h>
 
int StrcmpPointers(const char* p1, const char* p2)
{
  const unsigned char* s1 = (const unsigned char*) p1;
  const unsigned char* s2 = (const unsigned char*) p2;
 
  unsigned char c1 = 0;
  unsigned char c2 = 0;
 
  do
  {
    c1 = (unsigned char) *s1;
    c2 = (unsigned char) *s2;
    
    s1++;
    s2++;
 
    if (c1 == '\0')
    {
      return c1 - c2;
    }
  }
  while (c1 == c2);
 
  return c1 - c2;
}
 
int StrcmpIndex(const char* p1, const char* p2)
{
  const unsigned char* s1 = (const unsigned char*) p1;
  const unsigned char* s2 = (const unsigned char*) p2;
 
  unsigned char c1 = 0;
  unsigned char c2 = 0;
 
  size_t index = 0;
 
  do
  {
    c1 = (unsigned char) s1[index];
    c2 = (unsigned char) s2[index];
    index++;
 
    if (c1 == '\0')
    {
      return c1 - c2;
    }
  }
  while (c1 == c2);
 
  return c1 - c2;
}
 
char* VerifyResult(const int one, const int two, const int three)
{
  static char testResult[7];
 
  strcpy(testResult, "FAILED");
 
  if (((one > 0) && (two > 0) && (three > 0)) ||
      ((one < 0) && (two < 0) && (three < 0)) ||
      ((one == two) && (two == three) && (three == 0)))
  {
    strcpy(testResult, "PASSED");
  }
 
  return &testResult[0];
}
 
void RunTest(void)
{
  char* strings1[] = {
    "v5E2gQj1uU",
    "Ple19jNhRc", /* !!! */
    "NH3pz6mK2Y",
    "uhv5D3k3bl",
    "fXxEXAABbr",
    "eA4iMAWY0b", /* !!! */
    "24QmKOCS3Y",
    "ztiEQoic1o",
    "WjbZP81kKT",
    "F2B3Eww6lc"};
  char* strings2[] = {
    "oDXd4kpg2R",
    "Ple19jNhRc", /* !!! */
    "wJMZNuvNS3",
    "pHDyPJv8KD",
    "H1yvUdmfTt",
    "eA4iMAWY0b", /* !!! */
    "A5An4wQ8gU",
    "WGgW6NkIgD",
    "Wb5989AAzE",
    "jeAtaoS7is"};
 
  size_t i = 0;
  size_t N = sizeof(strings1) / sizeof(*strings1);
 
  int pointerRes = 0;
  int indexRes = 0;
  int stdRes = 0;
 
  for (i = 0; i < N; i++)
  {
    pointerRes = StrcmpPointers(strings1[i], strings2[i]);
    indexRes = StrcmpIndex(strings1[i], strings2[i]);
    stdRes = strcmp(strings1[i], strings2[i]);
 
    printf("s1 = '%s', s2 = '%s', res (ptr/idx/std): %d / %d / %d -> %s\n",
      strings1[i],
      strings2[i],
      pointerRes,
      indexRes,
      stdRes,
      VerifyResult(pointerRes, indexRes, stdRes));
  }
}
 
int main(void)
{
  RunTest();
  return 0;
}