C

Strings in C

C 137 views Dec 22, 2025 1 min read

A string in C is a sequence of characters stored in an array of type char and terminated by a null character ('\0').

Declaration of String

char str[20];

Initialization of String

char str[] = "Hello";
char str[6] = {'H','e','l','l','o','\0'};

Input and Output of Strings

Using scanf() and printf()

scanf("%s", str);
printf("%s", str);

Note: scanf() stops reading at whitespace.

Using gets() and puts()

gets(str);
puts(str);

Note: gets() is unsafe and not recommended.

Using fgets() (Recommended)

fgets(str, sizeof(str), stdin);

String Handling Functions

(Require #include )

FunctionDescription
strlen()Finds length
strcpy()Copies string
strcat()Concatenates strings
strcmp()Compares strings
strlwr()Converts to lowercase
strupr()Converts to uppercase

Example Program

#include 
#include 

int main() {
    char s1[20] = "Hello";
    char s2[20] = "World";

    strcat(s1, s2);
    printf("%s\n", s1);
    printf("Length = %d", strlen(s1));

    return 0;
}

Difference Between Character Array and String

  • Character array may not end with '\0'

  • String must end with '\0'

Summary

  • Strings are character arrays ending with null character

  • Stored using char type

  • string.h provides string functions

  • fgets() is safer for input

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