A string in C is a sequence of characters terminated by a null character ('\0'). Strings are stored in character arrays.

For example, the string "Hello" is stored as:

H   e   l   l   o   \0

1. Declaration of a String

Syntax

char string_name[size];

Example

char name[20];

This declares a string that can store up to 19 characters plus the null character ('\0').

2. Initialization of a String

Method 1: Using String Literal

char name[] = "Pradeep";

Method 2: Using Character Array

char name[] = {'P','r','a','d','e','e','p','\0'};

3. Reading and Displaying Strings

Using scanf() and printf()

 #include <stdio.h>

int main()
{
    char name[20];

    printf("Enter your name: ");
    scanf("%s", name);

    printf("Hello, %s", name);

    return 0;
}

Output

Enter your name: RahulHello, Rahul

Note: scanf("%s", name) reads only one word (stops at the first space).

4. Using fgets() to Read a Full Line

fgets() can read a string containing spaces.

 #include <stdio.h>

int main()
{
    char name[50];

    printf("Enter your full name: ");
    fgets(name, sizeof(name), stdin);

    printf("Name: %s", name);

    return 0;
}

Sample Output

Enter your full name: Rahul KumarName: Rahul Kumar

5. Common String Functions (<string.h>)

To use string functions, include:

#include &lt;string.h>
FunctionDescription
strlen()Returns the length of a string
strcpy()Copies one string to another
strcat()Concatenates (joins) two strings
strcmp()Compares two strings
strchr()Finds the first occurrence of a character
strstr()Finds a substring in a string

6. strlen() Example

 #include &lt;stdio.h>
#include &lt;string.h>

int main()
{
    char str[] = "Programming";

    printf("Length = %lu", strlen(str));

    return 0;
}

Output

Length = 11

7. strcpy() Example

 #include &lt;stdio.h>
#include &lt;string.h>

int main()
{
    char source[] = "C Language";
    char destination[20];

    strcpy(destination, source);

    printf("%s", destination);

    return 0;
}

Output

C Language

8. strcat() Example

 #include &lt;stdio.h>
#include &lt;string.h>

int main()
{
    char str1[30] = "Hello ";
    char str2[] = "World";

    strcat(str1, str2);

    printf("%s", str1);

    return 0;
}

Output

Hello World

9. strcmp() Example

 #include &lt;stdio.h>
#include &lt;string.h>

int main()
{
    char str1[] = "Apple";
    char str2[] = "Apple";

    if(strcmp(str1, str2) == 0)
        printf("Strings are Equal");
    else
        printf("Strings are Not Equal");

    return 0;
}

Output

Strings are Equal

10. Example Program

 #include &lt;stdio.h>
#include &lt;string.h>

int main()
{
    char name[30];

    printf("Enter your name: ");
    fgets(name, sizeof(name), stdin);

    printf("Your Name: %s", name);
    printf("Length: %lu", strlen(name));

    return 0;
}

Sample Output

Enter your name: Priya SharmaYour Name: Priya SharmaLength: 13

Note: If fgets() reads the newline (\n), strlen() includes it in the count. You can remove the newline if needed before processing the string.

Difference Between Character Array and String

Character ArrayString
Stores individual charactersStores a sequence of characters ending with '\0'
May or may not be null-terminatedAlways null-terminated
Example: {'A', 'B', 'C'}Example: "ABC"

Advantages of Strings

  • Easy to store and manipulate text.
  • Built-in library functions simplify string operations.
  • Widely used for names, addresses, messages, and file handling.
Category: MCA

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