函数说明 strcasecmp()用来比较参数s1和s2字符串,比较时会自动忽略大小写的差异。
返回值 若参数s1和s2字符串相同则返回0。s1长度大于s2长度则返回大于0 的值,s1 长度若小于s2 长度则返回小于0的值.
首先给出这两个函数的具体实现:
47 /*****************************************************************************/ 48 /* STRCASECMP() - Case-insensitive strcmp. */ 49 /*****************************************************************************/ 50 static int strcasecmp(const char* s1, const char* s2) 51 { 52 char c1, c2; 53 do { c1 = *s1++; c2 = *s2++; } 54 while (c1 && c2 && (tolower(c1) == tolower(c2))); 55 56 return tolower(c1) - tolower(c2); 57 } 58 59 /*****************************************************************************/ 60 /* STRNCASECMP() - Case-insensitive strncmp. */ 61 /*****************************************************************************/ 62 static int strncasecmp(const char* s1, const char* s2, size_t n) 63 { 64 char c1, c2; 65 66 if (!n) return 0; 67 68 do { c1 = *s1++; c2 = *s2++; } 69 while (--n && c1 && c2 && (tolower(c1) == tolower(c2))); 70 71 return tolower(c1) - tolower(c2); 72 }
- #include <stdio.h>
- #include <string.h>
- #include <ctype.h>
- int strcasecmp(const char *s1, const char *s2)
- {
- int c1, c2;
- do {
- c1 = tolower(*s1++);
- c2 = tolower(*s2++);
- } while(c1 == c2 && c1 != 0);
- return c1 - c2;
- }
- int main(void)
- {
- int n = 4;
- char str1[] = "Acef";
- char str2[] = "ACEFd";
- printf("strcasecmp(str1, str2) = %d/n", strcasecmp(str1, str2));
- return 0;
- }
函数说明:strncasecmp()用来比较参数s1和s2字符串前n个字符,比较时会自动忽略大小写的差异
返回值 :若参数s1和s2字符串相同则返回0 s1若大于s2则返回大于0的值 s1若小于s2则返回小于0的值
- #include <stdio.h>
- #include <string.h>
- #include <ctype.h>
- int mystrncasecmp(const char *s1, const char *s2, int n)
- {
- int c1, c2;
- do {
- c1 = tolower(*s1++);
- c2 = tolower(*s2++);
- } while((--n > 0) && c1 == c2 && c1 != 0);
- return c1 - c2;
- }
- int main(void)
- {
- int n = 4;
- char str3[] = "ABCf";
- char str4[] = "abcd";
- printf("mystrncasecmp(str3, str4, n) = %d/n", mystrncasecmp(str3, str4, n));
- return 0;
- }