C Library Functions for Strings. C comes with libraries of special functions, that we can use in our programs. These functions are stored in the string header file, which we include at the beginning of our program. Appends a copy of the source string to the destination string. The terminating null character in destination is overwritten by the first character of source, and a null-character is included at the end of the new string formed by the concatenation of both in destination. Destination and source shall not overlap. Parameters destination Pointer to the destination array, which should contain a C.
String is an array of characters. In this guide, we learn how to declare strings, how to work with strings in C programming and how to use the pre-defined string handling functions.
We will see how to compare two strings, concatenate strings, copy one string to another & perform various string manipulation operations. We can perform such operations using the pre-defined functions of “string.h” header file. In order to use these string functions you must include string.h file in your C program.
Method 2: The above string can also be defined as –
In the above declaration NULL character (0) will automatically be inserted at the end of the string.
What is NULL Char “0”?
'0' represents the end of the string. It is also referred as String terminator & Null Character.
String I/O in C programming
Read & write Strings in C using Printf() and Scanf() functions
Note: %s format specifier is used for strings input/output
Read & Write Strings in C using gets() and puts() functions
How To Use Strcpy In Dev C Online
C – String functions
C String function – strlen
size_t represents unsigned short
It returns the length of the string without including end character (terminating char ‘0’).
Example of strlen:
strlen vs sizeof
strlen returns you the length of the string stored in array, however sizeof returns the total allocated size assigned to the array. So if I consider the above example again then the following statements would return the below values.
strlen(str1) returned value 13.
sizeof(str1) would return value 20 as the array size is 20 (see the first statement in main function).
C String function – strnlen
size_t represents unsigned short
It returns length of the string if it is less than the value specified for maxlen (maximum length) otherwise it returns maxlen value.
Example of strnlen:Os x delete little snitch lyrics.
Length of string str1 when maxlen is 30: 13
Length of string str1 when maxlen is 10: 10
Have you noticed the output of second printf statement, even though the string length was 13 it returned only 10 because the maxlen was 10.
C String function – strcmp
It compares the two strings and returns an integer value. If both the strings are same (equal) then this function would return 0 otherwise it may return a negative or positive value based on the comparison.
If string1 < string2 OR string1 is a substring of string2 then it would result in a negative value. If string1 > string2 then it would return positive value.
If string1 string2 then you would get 0(zero) when you use this function for compare strings.
Example of strcmp:
C String function – strncmp
size_t is for unassigned short
It compares both the string till n characters or in other words it compares first n characters of both the strings.
Example of strncmp:
C String function – strcat
It concatenates two strings and returns the concatenated string.
Example of strcat:
C String function – strncat
It concatenates n characters of str2 to string str1. A terminator char (‘0’) will always be appended at the end of the concatenated string.
Example of strncat:
C String function – strcpy
It copies the string str2 into string str1, including the end character (terminator char ‘0’).
Example of strcpy:
C String function – strncpy
char *strncpy( char *str1, char *str2, size_t n)
size_t is unassigned short and n is a number.
Case1: If length of str2 > n then it just copies first n characters of str2 into str1.
Case2: If length of str2 < n then it copies all the characters of str2 into str1 and appends several terminator chars(‘0’) to accumulate the length of str1 to make it n.
Example of strncpy:
Dev c++ 18.104.22.168 for windows xp 7. Output:
C String function – strchr
It searches string str for character ch (you may be wondering that in above definition I have given data type of ch as int, don’t worry I didn’t make any mistake it should be int only. The thing is when we give any character while using strchr then it internally gets converted into integer for better searching.
Example of strchr:
C String function – Strrchr
It is similar to the function strchr, the only difference is that it searches the string in reverse order, now you would have understood why we have extra r in strrchr, yes you guessed it correct, it is for reverse only.
Now let’s take the same above example:
Why output is different than strchr? It is because it started searching from the end of the string and found the first ‘f’ in function instead of ‘of’.
C String function – strstr
How To Use Strcpy In Dev C Download
It is similar to strchr, except that it searches for string srch_term instead of a single char.
Example of strstr:
How To Use Strcpy In C
You can also use this function in place of strchr as you are allowed to give single char also in place of search_term string.
- Related Questions & Answers
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A string is a one dimensional character array that is terminated by a null character. The value of a string can be copied into another string. This can either be done using strcpy() function which is a standard library function or without it.
The program to copy a string without using strcpy() function is given as follows −
In the above program, a for loop is used to copy the contents of str1 into str2. This loop runs from 0 till null in str1. After the for loop, null is added to the end of the string in str2 and it is displayed. This is shown as follows.
The program to copy a string using the strcpy() function is given as follows.
In the above program, strcpy() function is used to copy the contents of str1 into str2. Then the contents of str2 are displayed. This is shown in the following code snippet.