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strncat() function in C:
- strncat( ) function in C language concatenates (appends) portion of one string at the end of another string. Syntax for strncat( ) function is given below.
char * strncat ( char * destination, const char * source, size_t num );
- Example :
strncat ( str2, str1, 3 ); – First 3 characters of str1 is concatenated at the end of str2.
strncat ( str1, str2, 3 ); – First 3 characters of str2 is concatenated at the end of str1.
- As you know, each string in C is ended up with null character (‘\0’).
- In strncat( ) operation, null character of destination string is overwritten by source string’s first character and null character is added at the end of new destination string which is created after strncat( ) operation.
Example program for strncat( ) function in C:
In this program, first 5 characters of the string “fresh2refresh” is concatenated at the end of the string “C tutorial” using strncat( ) function and result is displayed as “C tutorial fres”.
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#include <stdio.h> #include <string.h> int main( ) { char source[ ] = " fresh2refresh" ; char target[ ]= "C tutorial" ; printf ( "\nSource string = %s", source ) ; printf ( "\nTarget string = %s", target ) ; strncat ( target, source, 5 ) ; printf ( "\nTarget string after strncat( ) = %s", target ) ; } |
Output:
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Source string = fresh2refresh
Target string = C tutorial Target string after strcat( ) = C tutorial fres |
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 |