C99 删除 stricmp() 和 strnicmp()

C99标准中删除了stricmp()和strnicmp()函数，这两个函数在旧版本的C语言中用于比较字符串时忽略大小写。虽然在C99中这两个函数被删除了，但是我们可以使用其他方法来实现相同的功能。本文将介绍在C99中如何替代stricmp()和strnicmp()函数，并提供相应的案例代码。

c
#include 
#include 
#include 
int stricmp(const char* s1, const char* s2) {
   while (*s1 && *s2) {
       int diff = toupper(*s1) - toupper(*s2);
       if (diff != 0) {
           return diff;
       }
       s1++;
       s2++;
   }
   return toupper(*s1) - toupper(*s2);
}
int main() {
   char str1[] = "hello";
   char str2[] = "HELLO";
   
   int result = stricmp(str1, str2);
   
   if (result == 0) {
       printf("The strings are equal.\n");
   } else if (result < 0) {
       printf("String 1 is less than string 2.\n");
   } else {
       printf("String 1 is greater than string 2.\n");
   }
   
   return 0;
}

c
#include 
#include 
int main() {
   char str1[] = "hello";
   char str2[] = "HELLO";
   
   int result = strncasecmp(str1, str2, strlen(str1));
   
   if (result == 0) {
       printf("The strings are equal.\n");
   } else if (result < 0) {
       printf("String 1 is less than string 2.\n");
   } else {
       printf("String 1 is greater than string 2.\n");
   }
   
   return 0;
}