How to Use NULL Character in C with Examples

The Null character is an important character in C programming that symbolizes the end of an array or string. The Null character is not necessary for programming because it does not have a recognized symbol and has no related meaning. It is mostly used as a string terminator and takes 1 byte of memory with the value of 0.

Remember that the Null character shouldn’t be replaced with anything else, since doing so could result in a situation where the string’s end cannot be identified.

How to Use Null Character in C?

In C Programming, the Null character can be used in multiple ways, such as:

Terminating a String
Initializing an Array

1: Terminating a String

You can use the Null character in C Programming to terminate a string, here is an example that terminates the string “linuxhint” from the “welcome to linuxhint” string.

#include <stdio.h>

int main()

{

printf("welcome to \0 linuxhint"); //Adding '\0' in between, since it is an escape character,
// printf thinks this is the end point and stops itself.
return 0;

}

2: Terminating an Array

The Null character in C programming can also be used for terminating an array, and the example for such a case is given below:

#include <stdio.h>

#include <string.h>

int main() {

char arr[] = {'l','i','n', 'u', 'x', '\0','h', 'i', 'n', 't'}; // initialize the array with NULL characters
printf("\nlength of the array of characters is: %d",strlen(arr));
return 0;

}

3: I/O Operation

The Null character in C programming can also be used in I/O file operation to indicate the end of a file or stream:

#include <stdio.h>

int main() {

FILE *fp;
char c;
fp = fopen("file.txt", "r");
if (fp == NULL) {
printf("Error: File does not exist");
return 1;
}
while ((c = fgetc(fp)) != EOF) {
if (c == '\0') {
printf("End of file reached\n");
break;
}
printf("%c", c);
}
fclose(fp);
return 0;

}

How NULL Character Differs from ‘0’?

The constant ‘0‘ has different meanings in different contexts. It can either be used to compare a pointer to 0, also called null pointer constant, or can be used as a NULL character ‘\0’ to mark the end of an array or string in C programming.

Keep in mind that ‘\0′ and ‘0‘ are not the same things in C Programming. If you use ‘\0‘ in a code, it returns a character with an ASCII value of 0. While you will get a character with an ASCII value of 48 if you use the ‘0‘ in a program. Further, you will fail to terminate a string or array if you use ‘0‘ instead of ‘\0‘ in your program.

#include<stdio.h>

#include <string.h>

int main()
{
printf ("The value of \\0 is %d \n", '\0');
printf("The value of 0 is %d \n", '0');
return 0;
}

Conclusion

In C programming, a NULL character ends the character strings. The symbol for it is ‘\0‘ or NULL. Although the NULL character serves many different kinds of operations, its main objective is to end a string, array, or other C concept. This tutorial taught us what is the NULL character and how to use it in C programming. We also explored the difference between \0 and ‘0’ using an example.

How to Use NULL Character in C with Examples