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strncpy() function in C:
- strncpy( ) function copies portion of contents of one string into another string. Syntax for strncpy( ) function is given below.
char * strncpy ( char * destination, const char * source, size_t num );
- Example:
strncpy ( str1, str2, 4) – It copies first 4 characters of str2 into str1.
strncpy ( str2, str1, 4) – It copies first 4 characters of str1 into str2.
- If destination string length is less than source string, entire source string value won’t be copied into destination string.
- For example, consider destination string length is 20 and source string length is 30.
- If you want to copy 25 characters from source string using strncpy( ) function, only 20 characters from source string will be copied into destination string and remaining 5 characters won’t be copied and will be truncated.
Example program for strncpy( ) function in C:
In this program, only 5 characters from source string “fresh2refresh” is copied into target string using strncpy( ) function.
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#include <stdio.h> #include <string.h> int main( ) { char source[ ] = "fresh2refresh" ; char target[20]= "" ; printf ( "\nsource string = %s", source ) ; printf ( "\ntarget string = %s", target ) ; strncpy ( target, source, 5 ) ; printf ( "\ntarget string after strcpy( ) = %s", target ) ; return 0; } |
Output:
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source string = fresh2refresh
target string = target string after strncpy( ) = fresh |
C String functions:
- String.h header file supports all the string functions in C language. All the string functions are given below.
- Click on each string function name below for detail description and example programs.
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String functions
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Description
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| strcat ( ) | Concatenates str2 at the end of str1 |
| strncat ( ) | Appends a portion of string to another |
| strcpy ( ) | Copies str2 into str1 |
| strncpy ( ) | Copies given number of characters of one string to another |
| strlen ( ) | Gives the length of str1 |
| strcmp ( ) | Returns 0 if str1 is same as str2. Returns <0 if strl < str2. Returns >0 if str1 > str2 |
| strcmpi ( ) | Same as strcmp() function. But, this function negotiates case. “A” and “a” are treated as same. |
| strchr ( ) | Returns pointer to first occurrence of char in str1 |
| strrchr ( ) | last occurrence of given character in a string is found |
| strstr ( ) | Returns pointer to first occurrence of str2 in str1 |
| strrstr ( ) | Returns pointer to last occurrence of str2 in str1 |
| strdup ( ) | Duplicates the string |
| strlwr ( ) | Converts string to lowercase |
| strupr ( ) | Converts string to uppercase |
| strrev ( ) | Reverses the given string |
| strset ( ) | Sets all character in a string to given character |
| strnset ( ) | It sets the portion of characters in a string to given character |
| strtok ( ) | Tokenizing given string using delimiter |