strcat() vs strncat() in C++

In this tutorial, we will explore about strcat() and strncat() in the most usable language C++. We will also look at the difference between them.

strcat()

C++ is a computer language with a wide range of capabilities. strcat is an intrinsic function of the string class that, like other functions like as strncat and strcpy, has its own significance. These functions are critical because they are associated with code optimization and function calls. strcat() is a two-part function. str refers to the string, while cat refers to appending a copy of the string to the end or beginning of the string. strcat() appends a copy of the source string to the end of the destination string. In this programme, we will use two parameters:

1. dest01
2. src01

It will duplicate the source string and append it to the destination string. Src01's first character substitutes the terminating character at the end of dest01.

The value returned is: The strcat() function returns a reference to the dest01 target string.

C++ Program:

// To show strcat, use the CPP code.
#include <cstring>
#include <iostream>
using namespace std;
int main ()
{
	char dest01 [50] = "Hello Mr.";
	char src01 [50] = " saha...";


	strcat( dest01, src01 );
	cout << dest01 ;
	return 0;
}

Output:

Hello Mr. saha...

strncat()

The strncat() function in C++ appends the supplied number of characters to the end of one string.

We will utilise three parameters in this program:

1. Dest01
2. Src01
3. Count01

This adds the provided number of characters to the end of the dest01 string from the src01 string. The first character of the src01 string replaces the last character of the dest01 string.

strncat() returns a reference to the target string, dest01.

Return: The dest parameter of the strcat function returns the destination string. If the destination string is null, the strcat method will result in overlapping, which implies that all characters will be replaced with a copy of the source string. One caveat: the destination should never, ever overlap; if dest is an empty string, the possibility exists; otherwise, the destination should never, ever overlap. Furthermore, the Pointer to the target location must be large enough to hold or contain the concatenated content.

C++ Program:

// To show strncat (), use the CPP code.
#include <cstring> 
#include <iostream>


using namespace std;
int main()
{
	char dest01 [25] = "For instance,we";
	char src01 [50] = " will show working of strncat() extra words";
	
strncat ( dest01, src01, 29 );
	cout << dest01 ;
	return 0;
}

Output:

For instance,we will show working of strncat

What makes strncat() different from strcat()?

Many programmers believe strncat() is safer than strcat() because strcat() does not check for the amount of duplicated data and copies until it encounters a null terminator, which may cause a buffer overflow, whereas strncat() checks for the amount of copied data and copies just 'n' bytes.

C Program:

// C programme to show the distinction between strncat() and strcat()
#include <stdio.h>
#include <string.h>
// Main function
int main()
{
// considering two strings
char src01 [50] = "Hi man";
char dest01 [50] = "Hello";
char dest02 [50] = "Hello";
// printing of the string
printf( "Before strcat() function execution, " );
printf( "destination string : %s\n", dest01 );
	
// Generates the whole src01 string to dest01.
strcat( dest01, src01 ) ;


// Printing of the string
printf( "After strcat() function execution, " );
printf( "destination string : %s\n", dest01 );
// Printing the string
printf( "Before strncat() function execution, " );
printf( "destination string : %s\n", dest02 );
	
// Generates 3 characters from src01 to dest02 in this way.
strncat( dest02, src01, 3 );
	
// Printing the string
printf( "After strncat() function execution, " );
printf( "destination string : %s\n", dest02 );
	
return 0;
}

C++ Program:

// C++ programme to show the distinction between strncat() and strcat() ()
#include<bits/stdc++.h>
#include <string.h>
using namespace std;
// Main function
int main()
{


// considering two strings
char src01 [50] = "Hi man";
char dest01 [50] = "Hello";
char dest02 [50] = "Hello";
// Printing the string
cout << "Before strcat() function execution, " ;
cout <<  "destination string : " << dest01 ;
	
// Generates the whole src01 string to dest01 in this way.
strcat( dest01, src01 ) ;


// Printing of the string
cout << "\nAfter strcat() function execution, " ;
cout << "destination string : " << dest01 ;
// Printing the string
cout << "\nnBefore strncat() function execution, " ;
cout << "destination string : " << dest02 ;
	
// Generates 3 characters from src01 to dest02
strncat( dest02, src01, 3 );
	
// Printing the string
cout << "\nAfter strncat() function execution, " ;
cout <<  "ndestination string : " << dest02 ;
	
return 0;
}

Output:

Before strcat() function execution, destination string : Hello
After strcat() function execution, destination string : HelloHi man
nBefore strncat() function execution, destination string : Hello
After strncat() function execution, ndestination string : HelloHi

Conclusion

The strcat function in C++ is an extremely useful function that is included in the string.h header file's predefined library. The strncat function is also included in the string.h header file, however it differs from strcat() in terms of concatenation and appending source and destination. It has given the programmers the freedom to call the function at any point throughout the program's flow or outside the scope of the code block. In C++, strncat() is a string manipulation method defined in the cstring header file that operates on a string stored in a c-style char array and is used to append the first n characters of a string to the end of another string.