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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 on Oct 3 2018

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

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

#include "splashkit.h"
#include <string>
using namespace std;
int main()
//Convert the string "2017" to an integer 2017
string some_string = "2017";
int some_number = convert_to_integer(some_string);
write_line("The value of some_number is now:");
//Convert the string "3.14159265358979" to a double ~3.141593
string pi_string = "3.14159265358979";
double pi = convert_to_double(pi_string);
write_line("The value of pi is now:");
return 0;

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"
#include <string>
using namespace std;
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 ");
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

Another helpful set of functions provided by SplashKit’s utilities library is is_integer and is_number.

Consider the following.

#include "splashkit.h"
#include <string>
using namespace std;
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;

Its output is as follows.

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

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)
string buffer;
//Continue requesting user input until a valid whole number is entered.
while (1)
//Prompt the user with the message
//Read the user input as a string.
buffer = read_line();
//If the user input is a valid whole number, leave the loop.
if ( is_integer(buffer) )
//If the user input was not a valid whole number, ask them to enter a whole number.
write_line("Please enter a valid whole number.");
//Convert the user input to an integer before returning it.
return convert_to_integer(buffer);
int main()
int height;
height = read_integer("Enter your height in centimetres: ");
write("Your are ");
write_line("CM tall!");
return 0;

Manipulating strings

In addition to the functionality provided by C++‘s standard string library, SplashKit’s utilities library provides some extra string manipulation functions that can assist you with manipulating std::string data.

#include "splashkit.h"
#include <string>
using namespace std;
int main()
string name = "Richard";
string location = " Burwood";
//Convert "Richard" to "RICHARD"
name = to_uppercase(name);
//Convert "RICHARD" to "richard"
name = to_lowercase(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;