array, loop, function examples, C++ (gcc)

array, loop, function examples

#include <iostream>  // this is a header file that allows for i/o
using namespace std;

int main()
{
    // this is a constant variable. in other words,
    // when it is created, it is no longer allowed to 
    // be modified
    const int SIZE = 10;
    
    // this creates an array, which contains the number
    // of members defined by the SIZE variable
    // in C++, these types of arrays (called static arrays)
    // can only be created with a constant size. in other
    // words, if "const int SIZE = 10;" were "int SIZE = 10;"
    // you would get a compilation error. there are ways to
    // create arrays which can be created that way (called
    // dynamic arrays), but don't worry about them for now
    int intArray [SIZE];
    
    // right now, intArray contains 10 elements. it is
    // unitialized. this means that none of its elements
    // is set to anything in particular. you will not
    // get any compilation errors if you access one of
    // these elements, but you will essentially get garbage
    // if you try to access an element outside of the size
    // e.g. the 11th element, you will get a compilation error
    
    
    // lets now initialize the elements in the array, first
    // using a for loop (for sake of clarity, i am putting
    // each clause on its own line) :
    
    for(int i = 0;    // this creates an index variable and 
                      // initializes it to 0
        
        i < SIZE;     // during each iteration of the loop,
                      // i is compared to SIZE. if it is
                      // less than SIZE, the code inside
                      // the loop is executed. if not,
                      // the code is skipped
        
        i = i+1)      // at each step, i is incremented by
                      // 1. other ways of writing this are:
                      // i += 1, i++, ++i
        
    // putting this all in one line looks like:
    //      for(int i = 0; i < SIZE; i = i + 1)
        
    {
        // this code gets executed during each iteration of the loop
        
        // this means you are accessing the i-th element in the array
        // and setting it to i i.e. the 0 element is set to 0, the 8
        // element is set to 8. so on, so forth.
        intArray[i] = i;
    }
}


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