Week 2: Arrays and Functions
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Hi, Sorry for this late post. It is a week late, but on the other hand. This weekend there will be two posts! So.. A new week of Game Programming. This week we have gone through functions, arrays and pointers. This week have been more confusing and hard than the first week. I feel that the reason for that is that I didn’t give it much thought, or much time. The second week I didn’t have so many hours of studying as I should have had, which I later on understood. What are pointers? These are variables that hold memory addresses to a variable of the same data type. I will show you the syntax in the example under the explanation of what a function is. What is a function? They are statements which can take zero, one or more parameters. In every program there are at least one function, and that is the function main().
#include
void Swap(float* a, float* b)
{
float SwapHolder = *a;
*a = *b;
*b = SwapHolder;
}
int main(int argc, char* argv[])
{
float Num1 = 500, Num2 = 499;
Swap(&Num1, &Num2);
std::cout << "Number1: " << Num1 << " Number2: " << Num2 << std::endl;
return 0;
}
1st line of the code: I include a standard library. This specific library includes the functions so I can use std::cout. Line 3-8: Here I am declaring my function. This is called Swap and it is of the data type void. The only thing this function does is to Swap 2 numbers with each other. As you can see on Line 3 it says void Swap(float* a, float* b). This is a function with two parameters, which is declared as a and b with the data type float. The * after float is a syntax for creating a pointer. As said, a pointer will refer to a variables (with the same data type) memory address. If I then write the ‘&’-symbol before the variable that the pointer is equal to, then it will be de-referenced and will show the value that the pointer is pointing at. I know, this is extremely confusing. I will probably get this soon enough. This also demands extremely much time! Which I have been giving it. Line 11, 12 & 14: At line 11 I declare two variables Num1 and Num2 of the datatype float. I initialize the value 500 to Num1 and 499 to Num2. After this I call the function I made before, Swap, and within the parentheses I write the parameters which are connected to the variabels I made in the line before. I have an ‘&’-symbol before the parameters. This is a pointer thing, which I will talk about soon. What are arrays? Arrays are structures with a collection of elements of the same data type. Arrays are pretty easy. I will show you an example and then explain it:
#include
int main(int argc, char* argv[])
{
int myArray[5] = { 515, 2, 3, 4, 5 };
for (int i = 0; i < 5; i++)
{
std::cout << "myArray: [" << i << "] Value: " << myArray[i] << std::endl;
}
std::cin.get();
return 0;
}
In the int main function I have written: int myArray[5] = {515, 2, 3, 4, 5];. I have declared an array with 5 elements. The elements inside a array is numbered like: 0, 1, 2, 3, 4. So the 5th element is the 4th value in the array. So if I want to take out the value 5 from myArray I will have to write: I hope you have learned something new, at least I have! Cya all / Alex  |
