`HackerRank`

Profile

C++ Notes Section

Print Number of Digits after Decimal Point

#include <iostream>
#include <iomanip>

int main(int argc, char** argv)
{
    /* Set 6 digits after decimal point */
    std::cout << std::fixed;
    std::cout << std::setprecision(6); 
}

Access Individual Character in a std::string and putchar()
std::string.at() is a member function of class std::string;
takes an integer as index, returns the character at such position.

// string::at
#include <iostream>
#include <string>

int main ()
{
    std::string str("Test string");
    for (unsigned i=0; i<str.length(); ++i)
    {
        std::cout << std::quoted(str.at(i));
        // alternate way to print to the console:
        // putchar(str.at(i));
    }
    return 0;
}

Function putchar() acts like std::cout;
prints parsed argument to the console, as it 'puts' the character there.

Determine the Casing of a Character with isupper() and islower()
Prototype: int isupper(int c);
Checks if parameter c is an uppercase alphabetic letter.
Returns true or 1 if the parameter c is indeed uppercase.
Similarly:

islower();
isalpha();
toupper();
tolower();

Conversion between int and std::string
std::to_string(): converts number to std::string. std::to_string()
std::stoi(): converts std::string to an integer. std::stoi()

Function std::getline() for User Input
Use case:
std::getline(std::cin, user_name);
Calling prototype:
istream& getline (istream& is, string& str);

Access Individual Character in a std::string with .at() Method
Use case:
char elem = demo_str.at(0);
Calling prototype:
char& at (size_t pos);
const char& at (size_t pos) const;
It is also approachable using std::string::operator[].