C String

In C Programming, an one Dimensional array of characters followed by a null character \0 is called as string. In this article, we will show you, how to declare C string, access string elements, print elements of a strings in c with examples.

TIP: I suggest you to refer Array in C article to understand the Array concept

C string Declaration or Syntax

The syntax of a string in C Programming is as follows:

char String_Name [String_Size];

• String_Name: Please specify the name of a string. For example full_name, employee_name etc
• String_Size: Number of characters required for this string plus one (\0). For example, String_Size =10 then string can hold 9 characters.

For Example,

char full_name[50];

1. full_name is the string name
2. The size of a string is 50. It means, this string allows maximum 49 characters

C String Initialization

There are multiple ways to initialize a string C programming

// Declare C String without Size
char name[] = “Tutorial Gateway”;

// Declare String with Size
char name[50] = “Tutorial Gateway”;

// Declare String of Characters
char name[] = {‘T’, ‘u’, ‘t’, ‘o’, ‘r’, ‘i’, ‘a’, ‘l’, ‘G’, ‘a’, ‘t’, ‘e’, ‘w’, ‘a’, ‘y’, ‘\0’};

char name[16] = {‘T’, ‘u’, ‘t’, ‘o’, ‘r’, ‘i’, ‘a’, ‘l’,’ G’, ‘a’, ‘t’, ‘e’, ‘w’, ‘a’, ‘y’, ‘\0’};

You can also declare a string using pointers
char *str;
char *name = “hello world”;

C Program to Declare and Print Strings

In this C program, We are declaring the string in possible ways. Next, we are using printf statement to print those strings.

NOTE: You have to use %s to display the string as output. Or you use puts function

/* C String Example */
#include  <stdio.h>

int main(int argc, const char * argv[]) {
    // Declare C String without Size
    char name1[] = "Tutorial Gateway";
    
    // Declare String with Size
    char name2[50] = "Tutorial Gateway";
    
    // Declare String of Characters
    char name3[] = {'T','u','t','o','r','i','a','l','G','a','t','e','w','a','y', '\0'};
    
    char name4[16] = {'T','u','t','o','r','i','a','l','G','a','t','e','w','a','y', '\0'};
    
    printf("Name1: %s \n", name1);
    printf("Name2: %s \n", name2);
    printf("Name3: %s \n", name3);
    printf("Name4: %s \n", name4);
    return 0;
}

OUTPUT

Allow Users to enter String from Command line

In this program, we are allowing users to enter their own string. Next, we are printing that user given string as output.

/* C String Example */
#include  <stdio.h>

int main(int argc, const char * argv[])
{
    char name[50];
    printf("Please enter the Name : ");
    scanf("%s", name);
    
    printf("Name: %s \n", name);
    return 0;
}

OUTPUT

Access Elements of a Strings in C programming

In C programming, you can use indexes to access individual characters in a string. By this, you can insert, delete, or update any character at any given position.

/* C String Example */
#include  <stdio.h>

int main(int argc, const char * argv[])
{
    char name[50];
    int i = 0;
    
    printf("Please enter the Name : ");
    scanf("%s", name);
    
    while (name[i] != '\0')
    {
        printf("The Character at %d Index Position = %c \n", i, name[i]);
        i++;
    }
    return 0;
}

OUTPUT

ANALYSIS
First Iteration : while (name[i] != ‘\0’)
Here, i value is 0. It means, name[0] = h So, condition is True
It will print that character along with index position.
Next, i value will be incremented

Second Iteration: while (name[1] != ‘\0’)
while (e != ‘\0’) – Condition True

Third Iteration: while (name[2] != ‘\0’)
while (l != ‘\0’) – Condition True

Fourth Iteration: while (name[3] != ‘\0’)
while (l != ‘\0’) – Condition True

Fifth Iteration: while (name[4] != ‘\0’)
while (0 != ‘\0’) – Condition True

Sixth Iteration:while (name[5] != ‘\0’)
while (\0 != ‘\0’) – Condition is False. So, Compiler will exit from loop

C String length

In this C program, we are using the built-in string function strlen to find the length of a given string

/* C String Example */
#include  <stdio.h>
#include  <string.h>

int main(int argc, const char * argv[])
{
    char name[50];
    
    printf("Please enter the Name : ");
    scanf("%s", name);
    
    float len;
    len = strlen(name);
    printf("The Length of a Given String %s = %.f \n", name, len);

    return 0;
}

OUTPUT

C String Functions

Following are the list of string functions that are available in C Programming

1. memchr: Find first occurrence of a character and returns a pointer to it.
2. strcat: To concat or combine strings
3. strncat: This is same as above however, you can restrict the characters to add. It appends user specified characters to the end of a string.
4. strcmp: Used to compare two string to check whether they are equal or not.
5. strncmp: This is same as strcmp however, you can restrict the total number of characters to compare.
6. strcpy: Used to shallow copy the string
7. strncpy: This is same as strcpy. However, you can restrict the number of characters to copy.
8. strcoll: It compares two string using LC_COLLATE settings
9. strlen: Finds the length of a string
10. strlwr: Converts the string to lowercase
11. strpbrk: It find a first character in the first string that matches any character in a second string
12. strrev: This is used to reverse a given string.
13. strupr: Converts the string to uppercase