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# isprint() in C++

In C++, isprint() is a predefined function used for string and character handling. cstring is the header file required for string functions and cctype is the headerfile required for character functions. This function is used to check if the argument contains any printable characters. There are many types of printable characters in C++ such as:

• digits ( 0123456789 )
• uppercase letters ( ABCDEFGHIJKLMNOPQRSTUVWXYZ )
• lowercase letters ( abcdefghijklmnopqrstuvwxyz )
• punctuation characters ( !”#\$%&'()*+,-./:;?@[\]^_`{ | }~ )
• space ( )

Syntax:

```int isprint ( int c );
c : character to be checked.
Returns a non-zero value(true) if c is a printable
character else, zero (false).```

Time Complexity: O(n)
Auxiliary Space: O(1)

Given a string in C++, we need to calculate the number of printable characters in the string. Algorithm

1. Traverse the given string character by character upto its length, check if character is a printable character.
2. If it is a printable character, increment the counter by 1, else traverse to the next character.
3. Print the value of the counter.

Examples:

```Input : string = 'My name \n is \n Ayush'
Output : 18

Input :string = 'I live in \n Dehradun'
Output : 19```

## CPP

 `// CPP program to count printable characters in a string``#include ``#include ``#include ``using` `namespace` `std;` `// function to calculate printable characters``void` `space(string& str)``{``    ``int` `count = 0;``    ``int` `length = str.length();``    ``for` `(``int` `i = 0; i < length; i++) {``        ``int` `c = str[i];``        ``if` `(isprint(c))``            ``count++;``    ``}``    ``cout << count;``}` `// Driver Code``int` `main()``{``    ``string str = ``"My name \n is \n Ayush"``;``    ``space(str);``    ``return` `0;``}`

Output

`18`