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Useful Utilities

In this article, we discuss useful utilities that you can use to convert, check and manipulate common data types in SplashKit programs.
Written by: Richard Denton and others
Last updated: October 2024

SplashKit’s Utilities library provides a range of useful functions that can assist you with converting, checking, and manipulating common data types in your SplashKit program.

These functions are useful in many areas of programming.

Converting a string to a number

Section titled “Converting a string to a number”

SplashKit provides two useful functions for handling the conversion of a string to either an int or a double.

#include "splashkit.h"


int main()
{
    // Convert the string "2017" to an integer 2017
    string some_string = "2017";
    int some_number = convert_to_integer(some_string);


    write("The value of some_number is: ");
    write_line(some_number);


    // Convert the string "3.14159265358979" to a double ~3.141593
    string pi_string = "3.14159265358979";
    double pi = convert_to_double(pi_string);


    write("The value of pi is: ");
    write_line(pi);


    return 0;
}

Usage scenario: converting user input to an integer

Section titled “Usage scenario: converting user input to an integer”

Consider you want to write a program that accepts two numbers as input from a user, multiplies them, and outputs the result. One way to accomplish this is to use SplashKit’s Convert To Integer function.

#include "splashkit.h"


int main()
{
    // User input will initially be stored in these two strings.
    string snum_1, snum_2;


    // And then it will be converted and stored in these integers.
    int inum_1, inum_2, result;


    // Read user input
    write("Enter first number: ");
    snum_1 = read_line();
    write("Enter second number: ");
    snum_2 = read_line();


    // Convert user input to integers
    inum_1 = convert_to_integer(snum_1);
    inum_2 = convert_to_integer(snum_2);


    // Compute the result
    result = inum_1 * inum_2;


    // Output the results
    write(snum_1 + " multiplied by " + snum_2 + " equals ");
    write_line(result);


    return 0;
}

The same can be achieved for decimal numbers, simply by swapping convert_to_integer with convert_to_double, and using the appropriate data types.

//...


//Don't use integers, instead use doubles
double inum_1, inum_2, result;


//...


inum_1 = convert_to_double(snum_1);
inum_2 = convert_to_double(snum_2);


//...

Checking if a string is a number

Section titled “Checking if a string is a number”

Another helpful set of functions provided by SplashKit’s utilities library is Is Integer and Is Number.

Consider the following.

#include "splashkit.h"


int main()
{
    string message_1 = "9781273";
    string message_2 = "23129739.13";
    string message_3 = "Hello world.";


    if (is_integer(message_1))
        write_line("Message 1 contains an integer!");


    if (is_number(message_1))
        write_line("Message 1 contains a number!");


    if (not is_integer(message_2))
        write_line("Message 2 is not an integer!");


    if (is_number(message_2))
        write_line("Message 2 contains a number!");


    if (not is_integer(message_3))
        write_line("Message 3 is not an integer!");


    if (not is_number(message_3))
        write_line("Message 3 is not a number!");


    return 0;
}

The terminal output should be:

Message 1 contains an integer!
Message 1 contains a number!
Message 2 is not an integer!
Message 2 contains a number!
Message 3 is not an integer!
Message 3 is not a number!

Usage scenario: accept user input as a number

Section titled “Usage scenario: accept user input as a number”

SplashKit’s Is Integer and Is Number functions can be used to validate user input, ensuring the user always enters a valid data type.

#include "splashkit.h"
#include <string>


using namespace std;


/**
 * Reads input from a user, only allowing whole numbers.
 * @prompt string     - The string to display to the user.
 * @return int
 */
int read_integer(string prompt)
{


    // Prompt the user with the message
    write(prompt);


    // Read the user input as a string.
    string line = read_line();


    // Check if user input is a valid whole number, loop until it is.
    while (!is_integer(line))
    {
        write_line("Please enter a whole number.");


        write(prompt);
        line = read_line();
    }


    // Convert the user input to an integer before returning it.
    return convert_to_integer(line);
}


int main()
{
    int height;


    height = read_integer("Enter your height in centimetres: ");
    write("You are ");
    write(height);
    write_line("CM tall!");


    return 0;
}

Manipulating strings

Section titled “Manipulating strings”

In addition to the functionality provided by each language’s standard library (The string library in C++, and the System library in C#), SplashKit’s utilities library provides some extra string manipulation functions that can assist you with manipulating string data.

#include "splashkit.h"


int main()
{
    string name = "Richard";
    string location = "        Burwood";


    // Convert "Richard" to "RICHARD"
    name = to_uppercase(name);
    write_line(name);


    // Convert "RICHARD" to "richard"
    name = to_lowercase(name);
    write_line(name);


    // Remove all of the empty spaces at the start of "       Burwood".
    write_line("Before: " + location);
    location = trim(location);
    write_line("After: " + location);


    return 0;
}