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.
String Declaration
Method 1: C program to encrypt and decrypt the string using Caesar Cypher Algorithm. We have used a simple method of adding and subtracting a key value for encryption and decryption. For encrypting a string, key-value ‘2’ is added to the ASCII value of the characters in the string. String ในภาษา c/c ในภาษา c/c ตัวแปร String คือการนําตัวแปรชนิด char หลายๆตัวมาต่อกัน หรืออาจจะเรียกว่า char array โดยจะบอกจุดสิ้นสุดของ String ด้วยตัวอักษร(char) ' 0'.
Method 1:
Method 2: The above string can also be defined as –
![Dev c++ online Dev c++ online](/uploads/1/3/3/9/133935032/396527030.jpeg)
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
Output:
Note: %s format specifier is used for strings input/output
Read & Write Strings in C using gets() and puts() functions
C – String functions
C String function – strlen
Syntax:
size_t represents unsigned short
It returns the length of the string without including end character (terminating char ‘0’).
It returns the length of the string without including end character (terminating char ‘0’).
Example of strlen:
Output:
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 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.
3utools flash failed.
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
Syntax:
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.
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:
Output:
Length of string str1 when maxlen is 30: 13
Length of string str1 when maxlen is 10: 10
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.
If string1 string2 then you would get 0(zero) when you use this function for compare strings.
Example of strcmp:
Output:
C String function – strncmp
https://swnew843.weebly.com/little-snitch-334-keygen.html. 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.
It compares both the string till n characters or in other words it compares first n characters of both the strings.
Example of strncmp:
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Output:
C String function – strcat
It concatenates two strings and returns the concatenated string.
Example of strcat:
Output:
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:
Output:
C String function – strcpy
It copies the string str2 into string str1, including the end character (terminator char ‘0’).
Autotune download. Example of strcpy:
Output:
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.
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:
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:
Output:
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:
Output:
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
String.h In Dev C Pdf
It is similar to strchr, except that it searches for string srch_term instead of a single char.
Example of strstr:
Output:
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.
I am trying to learn C++ and am trying to figure out how to use strings and if statements together. Here's the code I'm trying to play around with:
Every time I type in no, the statement 'You open the door' pops up. Anybody know what I'm doing wrong?
Thanks
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mike_2000_172,669
String In Dev C++
First of all, for any type (string or other), the statement 'if ( a = b )' does not check whether a is equal to b, it assigns the value of b to a, and returns the final value a (which is also the value of b). Auto tune not pulling up in pro tools and equipment. The single = sign is an assignment operator, not a comparison operator. The comparison for equality is , i.e. double equal sign.
String.h In Dev C Language
Second, the strings that you are using are so-called C-strings (kept for legacy support of C code in C++). The proper string to use is the class 'std::string' (in the '#include <string>' header. Using these, your code will work (with the double equal sign instead of single equal sign for comparisons).
Third, if you have to use 'char *', i.e. C-strings, then there is no equality operator for it, so 'a 'yes' will not work. The proper function to compare two C-strings is strcmp(), which will return 0 if they are equal. Thus:
Finally, and most importantly, having 'char* a;' does not initialize 'a'. 'a' is a pointer to an array of characters (char). By not initializing it, you have a pointer that points nowhere (well it points somewhere, but not somewhere that it should point to, because the memory at that address will be used for something else and using 'a' uninitialized will corrupt your program). So, you need to initialize it by giving some space for it. Since you are beginning to learn, I'm not sure how much I should or could explain, so I will just say that you should replace line 5 by this:
But, frankly, using std::string is highly recommended here.