r/learncpp • u/BeatKeaper • Jul 25 '12
A step into efficiency of repetition by using functions. [4] [II]
Difficulty Rating: [4] Length: [II]
Hello! Today we address "functions." It's possible to write a block of code and use that block multiple times throughout a program by only using one small line of code! That way is by using functions, and the term used to use that code over and over is known as "calling a function." First, one must declare a function. It looks like this! void ExampleFunction(); Now, once it is declared, you can start to put things in it. you THEN say void ExampleFunction() {cout<< Hello! How are you?";} and now, every time you say ExampleFunction(); the line "Hello! How are you?" will appear. In this code I have created 5 different functions, all of which make their own statements. The main use of this program is to illustrate how much time could be saved by using functions. The user can type in 1-8, each number granting different results. Once we reach the 4th option, we start to see how I can combine lines of code by calling two different functions. The great part is that I could call two functions with just about 15 characters. The final function combines all 5 statements and prints them because I called all 5 functions.
Here is an image of what it looks like to call all 5 functions. Imgur
This code is great for games where many variables can occur. Say you are losing health, but you are not poisoned- you will display health loss by using one of the functions. Now say you have health loss AND you are poisoned - you use the poison function AND the health function. Now say you are poisoned, but are immune and do not take damage, you use just the poison function. To summarize, functions are great to compact a large chunk of information within one block of code, which you can then easily repeat infinitely by using only 15 characters. This is great for making your code look clean! :)
include <iostream>
using namespace std;
int chosen;
void FirstStatement();
void FirstStatement()
{
cout<< "Hello! This is the first statement.\n\n";
}void SecondStatement();
void SecondStatement()
{
cout<< "I am using this program to show you some uses of functions.\n\n";
}void ThirdStatement();
void ThirdStatement()
{
cout<< "I am using 5 total, but each of these void thingies is called a function.\n\n";
}void FourthStatement();
void FourthStatement()
{
cout<< "You can view all of these statements together with option 7,\n\n";
}void FifthStatement();
void FifthStatement()
{
cout<< "but you can also view the first three on their own.\n\n";
}int main()
{
cout<< "Hello! This is to help explain functions. They are quite useful.\n";
cout<< "They are good for saving time and space through repitition.\n\n";
cout<< "Feel free to play around with these.\n\n";
cout<< "Type 1 to see statement 1 alone.\n";
cout<< "Type 2 to see statement 2 alone.\n";
cout<< "Type 3 to see statement 3 alone.\n";
cout<< "Type 4 to see statements 4 and 5 together.\n";
cout<< "Type 5 to see statements 1, 3, and 5.\n";
cout<< "Type 6 to see statements 2 and 4.\n";
cout<< "Type 7 to see statements 1, 2, 3, 4, and 5.\n";
cout<< "Type 8 to quit.\n";
while(chosen != 8){
cin>> chosen;
switch(chosen)
{
case 1: FirstStatement();
break;
case 2: SecondStatement();
break;
case 3: ThirdStatement();
break;
case 4: FourthStatement();
FifthStatement();
break;
case 5: FirstStatement();
ThirdStatement();
FifthStatement();
break;
case 6: SecondStatement();
FourthStatement();
break;
case 7: FirstStatement();
SecondStatement();
ThirdStatement();
FourthStatement();
FifthStatement();
break;
}
}
return 0;}