function
<cstring>
strncmp
int strncmp ( const char * str1, const char * str2, size_t num );
Compare characters of two strings
Compares up to num characters of the C string str1 to those of the C string str2.
This function starts comparing the first character of each string. If they are equal to each other, it continues with the following pairs until the characters differ, until a terminating null-character is reached, or until num characters match in both strings, whichever happens first.
Parameters
- str1
- C string to be compared.
- str2
- C string to be compared.
- num
- Maximum number of characters to compare.
size_t is an unsigned integral type.
Return Value
Returns an integral value indicating the relationship between the strings:
| return value | indicates |
|---|
<0 | the first character that does not match has a lower value in str1 than in str2 |
0 | the contents of both strings are equal |
>0 | the first character that does not match has a greater value in str1 than in str2 |
Example
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| /* strncmp example */ #include <stdio.h> #include <string.h> int main () { char str[][5] = { "R2D2" , "C3PO" , "R2A6" }; int n; puts ("Looking for R2 astromech droids..."); for (n=0 ; n<3 ; n++) if (strncmp (str[n],"R2xx",2) == 0) { printf ("found %s\n",str[n]); } return 0; }
|
Output:
Looking for R2 astromech droids... found R2D2 found R2A6 |
See also
- strcmp
- Compare two strings (function)
- memcmp
- Compare two blocks of memory (function)
- strrchr
- Locate last occurrence of character in string (function)
- strspn
- Get span of character set in string (function)