Array in C++ / review

An array contains multiple objects of identical types stored sequentially in memory. The individual objects in an array, referred to as array elements, can be addressed using a number, called index or subscript. The array is the most commonly used data storage structure. It helps to see how object-oriented programming and data structures relate to each other.

Like a regular variable, an array must be declared before it is used. A typical declaration for an array in C++ is: type name [ no of elements]; You can create an array from any type with the exception of some special types. An array always occupies a contiguous memory space. To know how much memory spaces an array needs, for example, if we have an array of 10 elements, this space is 10*sizeof(float) = 40 bytes.

when declaring an array, there is a possibility to assign initial values to each one of its elements. To access the values of an array; being able to both read and modify its value by using this format : name[index]

# include using namespace std; int main() { int n[10]; for( int i=0;i<10;i++) n[i] =0; cout<<“Element”<<setw(13)<<“value”<<endl; for(int j=0; j<10;j++) cout<<setw(7)<<j<<setw(13)<<n[j]<<endl; return 0; }

 How to assign initial values to a char array : char name[ ] = “welcome back"; This definition is equivalent to char name[ ] = {‘w’, ‘e’, ‘l’, ‘c’, ‘o’, ‘m’, ‘e’, ‘ ‘, ‘b’, ‘a’, ‘c’, ‘k’, ‘\0’};

Multidimensional arrays can be described as "arrays of arrays". Multidimensional arrays are not limited to two indices. #define WIDTH 3 #define HEIGHT 2 int table [HEIGHT][WIDTH]; int n,m; int main () { for (n=0;n<HEIGHT; n++) for (m=0; m<WIDTH; m++) { table [n][m]=(n+1)*(m+1); } return 0; }

Array Advantages: Easier to declare and use. Can be used with most of the data types. Array Disadvantages: Fixed size data. Ex: if the number of elements to be stored are more than the maximum size, the array cannot accommodate those new values.

Functions/ review

FUNCTIONS If you are looking to provide a solution for a more complex problem, it will help to divide the problem into smaller units. Functions can be defined in any order, however, the first function is normally main. Definition syntax: type name ( parameter1, parameter2,...) { statements }

Prototype and Definition In a function definition, the function header is similar in form to the prototype(declaration) of a function. State the differences between the prototype and function declaration? When do the function must be declare? The prototype provides the compiler with all the information it needs when a function is called, what are these information and what will happen after that? Can the function declaration be omitted ? When ?

■ RETURN VALUE OF FUNCTIONS When a function is called, an argument of the same type as the parameter must be passed to the function for each parameter. Note: the arguments can be also any kind of expressions. If the function is any type other than void, the return statement will cause the function to return a value to the function that called it. When the program flow reaches a return statement or the end of a function code block, where it goes?

■ PASSING ARGUMENTS Passing values to a function when the function is called is referred to as passing by value, does it access the object it self directly? However, function arguments can also be passed by reference.

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Other topics to review Overloading function. Inline function. Recursion. Default arguments.

Any Question? Refer to chapter 1 of the book for further reading