C Tutorial/string.h/strncmp
strncmp
Item Value Header file string.h Declaration int strncmp(const char *str1, const char *str2, size_t count); Function lexicographically compares not more than count characters and returns an integer as follows: Value Meaning <0 str1 is less than str2 0 str1 is equal to str2 >0 str1 is greater than str2
Using strcmp and strncmp
#include <stdio.h>
#include <string.h>
int main()
{
const char *s1 = "asdfasdfasdf";
const char *s2 = "fdafdsafdsa";
const char *s3 = "abced";
printf("%s%s\n%s%s\n%s%s\n\n%s%2d\n%s%2d\n%s%2d\n\n",
"s1 = ", s1, "s2 = ", s2, "s3 = ", s3,
"strcmp(s1, s2) = ", strcmp( s1, s2 ),
"strcmp(s1, s3) = ", strcmp( s1, s3 ),
"strcmp(s3, s1) = ", strcmp( s3, s1 ) );
printf("%s%2d\n%s%2d\n%s%2d\n",
"strncmp(s1, s3, 6) = ", strncmp( s1, s3, 6 ),
"strncmp(s1, s3, 7) = ", strncmp( s1, s3, 7 ),
"strncmp(s3, s1, 7) = ", strncmp( s3, s1, 7 ) );
return 0;
}s1 = asdfasdfasdf s2 = fdafdsafdsa s3 = abced strcmp(s1, s2) = -5 strcmp(s1, s3) = 17 strcmp(s3, s1) = -17 strncmp(s1, s3, 6) = 17 strncmp(s1, s3, 7) = 17 strncmp(s3, s1, 7) = -17
