Javatpoint Logo
Javatpoint Logo

Strcat() function in C

Programmers may easily concatenate two strings using the strcat() function in C, which is a potent tool for manipulating strings. This function accepts two input strings and appends the second string's content to the end of the first string. A single, longer string made up of the characters from both input strings is the outcome. You must include the string.h header file to use strcat(). But to prevent buffer overflow and unpredictable behavior, it is essential to make sure the first string has enough memory to hold the concatenated content. In this article, we'll study several crucial string concatenation principles in C and go in-depth on the strcat() method.

Concatenating strings is a fundamental programming process, particularly when working with text-based data. Strings in C are character arrays that are ended by the null character "0". You may produce longer and more insightful text outputs by adding one string to another with the strcat() method.

The strcat(first_string, second_string) function concatenates two strings and result is returned to first_string.

first_string: The concatenated result will be saved in this string, which is a reference to the target string. The second_string's content is added to the end of the first_string by the function. Making ensuring that the first_string has adequate memory to store the concatenated information is crucial.

Second_string: It is a reference to the source string that will be added to the end of the first_string. During concatenation, the initial second_string is not modified.


Value of first string is: helloc


The required header files are included in the source code, stdio.h for standard input/output routines and string.h for string manipulation operations like strcat().

There are two declared character arrays (ch and ch2). The first array, ch, begins with the letters "hello" and ends with the specifically specified null character "0". The letter "c" is found in the second array, ch2, followed by the null character "0".

The two strings are concatenated using the strcat(ch, ch2) function. The characters from ch2 will be added to the end of ch in accordance with the behavior of the function. The adjusted ch array will appear as follows concatenation: "helloc0" (remember that "0" stands for the null terminator).

The changed ch array is then displayed using the printf() function, producing the following output: "Value of the first string is: helloc".


In conclusion, developers may effectively deal with character arrays due to the C programming language's robust string manipulation capabilities like strcat(). The strcat() method is designed to join two strings together by merging the end of the second string with the contents of the first. Care must be taken while utilizing this function to prevent buffer overflow and undefinable behavior.

The strcat() function successfully combined the strings "hello" and "c" in the supplied code sample, producing the output "helloc". It emphasizes how crucial it is to check that the destination string has enough room to hold the combined result.

When working with unknown or dynamic data, developers should always evaluate the sizes of the source and destination arrays before using strcat() and may want to use strncat() with a set maximum length.

There are several string manipulation functions available in the C language, each with special benefits and applications. The creation of reliable and secure software will be facilitated by understanding these functions and using safe coding techniques. Understanding string handling, a fundamental programming component, enables programmers to build more complex and dependable systems across various industries. As their exploration of C programming progresses, aspiring programmers should get more familiar with the language's features and gain proficiency in it.

Next TopicC strcmp()

Youtube For Videos Join Our Youtube Channel: Join Now


Help Others, Please Share

facebook twitter pinterest

Learn Latest Tutorials


Trending Technologies

B.Tech / MCA