035.cpp

// STL : cctype library.

#include <iostream>
#include <cctype>

int main()
{
    // demonstrating the function declared in cctype header file
    // functions : isalpha(), isblank(), iscntrl(), isdigit(), isgraph(), islower(),
    // isprint(), ispunct(), isspace(), isupper(), isxdigit(), tolower(), toupper()

    // 1. isalpha():
    char ch = 'a';
    int a = 2;
    std::cout << isalpha(ch) << std::endl; // returns more than 0 for being true
    std::cout << isalpha(a) << std::endl;  // returns 0 because it is not a alphabet

    // 2. isblank()
    ch = ' ';
    std::cout << isblank(ch) << std::endl; // returns more than 0 because ch contains a blank character
    std::cout << isblank(a) << std::endl;  // returns 0 because a contains a digit

    // 3. iscntrl()  : examples of control characters - '\n', '\t', '\b'
    ch = '\t';
    std::cout << iscntrl(ch) << std::endl;  // return more than 0 because ch contains a control character
    std::cout << iscntrl(' ') << std::endl; // returns 0 because space is not a control character

    /// 4. isdigit()
    ch = '6';
    std::cout << isdigit(6) << std::endl;  // returns 0 as 6 is an integer
    std::cout << isdigit(ch) << std::endl; // returns 1 as '6' is a digit

    // 5. isgraph()
    // ch contains 6
    std::cout << isgraph(ch) << std::endl; // true condition
    ch = '\t';
    std::cout << isgraph(ch) << std::endl; // false condition

    // 6. islower()
    ch = 'i';
    std::cout << islower(ch) << std::endl;  // true condition
    std::cout << islower('I') << std::endl; // false condition

    // 7. isprint()
    ch = 't';
    std::cout << isprint(ch) << std::endl;   // true condition
    std::cout << isprint('\t') << std::endl; // false condition

    // 8. ispunct()
    std::cout << ispunct(',') << std::endl; // true
    std::cout << ispunct('+') << std::endl; // true
    std::cout << ispunct('8') << std::endl; // false

    // 9. isspace()
    std::cout << isspace(' ') << std::endl; // true
    std::cout << isspace('p') << std::endl; // false

    // 10 . isupper()
    ch = 'I';
    std::cout << isupper(ch) << std::endl;  // true condition
    std::cout << isupper('i') << std::endl; // false condition

    // 11. isxdigit()
    ch = '0';
    std::cout << isxdigit(ch) << std::endl; // true condition

    // 12. tolower()
    std::cout << (char)(tolower('T')) << std::endl;

    // 13. toupper()
    std::cout << (char)(toupper('t')) << std::endl;
    return 0;
}