> ## Content Index > Fetch the complete content index at: https://developerinsider.co/llms.txt > Use this file to discover other available public pages before exploring further. # Strings - C Programming - URL: https://developerinsider.co/strings-c-programming/ - Published: 2016-03-28T11:19:00.000Z - Updated: 2018-06-24T05:01:17.000Z - Author: Vineet Choudhary - Tags: Primary, C Programming ## 1\. What is String? Strings are arrays of characters. Each member of array contains one of characters in the string. **Example** ```c #include main() { char name[20]; printf("Enter your name : "); scanf("%s",name); printf("Hello, %s , how are you ?\n",name); } ``` Output Results: ``` Enter your name : Vineet Hello, Vineet, how are you ? ``` If user enters "Vineet" then the first member of array will contain 'V' , second cell will contain 'i' and so on. C determines end of a string by a zero value character. We call this character as `NULL` character and show it with `\0` character. (It's only one character and its value is 0, however we show it with two characters to remember it is a character type, not an integer). Equally we can make that string by assigning character values to each member. ```c name[0]='B'; name[1]='r'; name[2]='i'; name[3]='a'; name[4]='n'; name[5]='\0'; ``` As we saw in above example placeholder for string variables is `%s`. Also we will not use a `&` sign for receiving string values. ## 2\. Point to Note While entering the string using `scanf()` we must be cautious about two things: - The length of the string should not exceed the dimension of the character array. This is because the C compiler doesn’t perform bounds checking on character arrays. - `scanf()` is not capable of receiving multi-word strings. Therefore names such as "Vineet Choudhary" would be unacceptable. The way to get around this limitation is by using the function `gets()`.The usage of functions `gets()` and its counter part `puts()` is shown below. ```c #include main( ) { char name[25] ; printf ("Enter your full name ") ; gets (name) ; puts ("Hello!") ; puts (name) ; } ``` And here is the output... ``` Enter your name Vineet Choudhary Hello! Vineet Choudhary ``` The program and the output are self-explanatory except for the fact that, `puts()` can display only one string at a time (hence the use of two `puts()` in the program above). Also, on displaying a string, unlike `printf()`, `puts()` places the cursor on the next line. Though `gets()` is capable of receiving only one string at a time, the plus point with `gets()` is that it can receive a multi-word string. If we are prepared to take the trouble we can make `scanf()` accept multi-word strings by writing it in this manner: ```c char name[25] ; printf ("Enter your full name ") ; scanf ("%[^\n]s", name) ; ``` Though workable this is the best of the ways to call a function, you would agree. ## 3\. Standard Library String Functions With every C compiler a large set of useful string handling library functions are provided in `string.h` file. - `strlen` \- Finds length of a string - `strlwr` \- Converts a string to lowercase - `strupr` \- Converts a string to uppercase - `strcat` \- Appends one string at the end of another - `strncat` \- Appends first n characters of a string at the end of another - `strcpy` \- Copies a string into another - `strncpy` \- Copies first n characters of one string into another - `strcmp` \- Compares two strings - `strncmp` \- Compares first n characters of two strings - `strcmpi` \- Compares two strings without regard to case ("i" denotes that this function ignores case) - `stricmp` \- Compares two strings without regard to case (identical to strcmpi) - `strnicmp` \- Compares first n characters of two strings without regard to case - `strdup` \- Duplicates a string - `strchr` \- Finds first occurrence ofa given character in a string - `strrchr` \- Finds last occurrence ofa given character in a string - `strstr` \- Finds first occurrence of a given string in another string - `strset` \- Sets all characters ofstring to a given character - `strnset` \- Sets first n characters ofa string to a given character - `strrev` \- Reverses string ## 4\. Example The following example uses some of the above-mentioned functions − ```c #include #include int main () { char str1[12] = "Hello"; char str2[12] = "World"; char str3[12]; int len ; /* copy str1 into str3 */ strcpy(str3, str1); printf("strcpy( str3, str1) : %s\n", str3 ); /* concatenates str1 and str2 */ strcat( str1, str2); printf("strcat( str1, str2): %s\n", str1 ); /* total lenghth of str1 after concatenation */ len = strlen(str1); printf("strlen(str1) : %d\n", len ); return 0; } ``` When the above code is compiled and executed, it produces the following result − ``` strcpy( str3, str1) : Hello strcat( str1, str2): HelloWorld strlen(str1) : 10 ``` ## 5\. Examples | Example Statement for String in C Language | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [1\. Check whether two strings are anagrams or not](https://developerinsider.co/check-whether-two-strings-are-anagrams-or-not-c-language-programming/) | | [2\. Find a frequenct of character in string](https://developerinsider.co/find-a-frequenct-of-character-in-string-c-language-programming/) | | [3\. Insert substring into a string](https://developerinsider.co/insert-substring-into-a-string-c-language-programming/) | | [4\. Substring from a position to length](https://developerinsider.co/substring-from-a-position-to-length-c-language-programming/) | | [5\. Check if a string is a subsequence of another string](https://developerinsider.co/check-if-a-string-is-a-subsequence-of-another-string-c-language-programming/) | | [6\. Delete vowels from a string](https://developerinsider.co/delete-vowels-from-a-string-c-language-programming/) | **Next** \- [Functions](https://developerinsider.co/functions-c-programming/)