Arrays

The array data structure Array is a collection of elements, that have the same data type Integers (int) Floating point numbers (float, double) Characters (char) // character array is also known as a string etc Array elements are indexed using integers starting from zero Accessing a member of array is done by using its’ index 1-dimensional arrays are also known as vectors 2-dimensional arrays are also known as matrixes 20152

Declaring an array The size of an array is set at the time of declaration by the number in the square brackets int numbers[10] // an array for 10 integers char textField[15] // array for chars The arrays can be N-dimensional and the lengths of the dimentions may vary int elements[N][M][K] 20153

1-dimentional array (vector) The number in the square brackets sets the size for the array int numbers[5]; When accessing a member of the array, we specify the index of the element in the square brackets numbers[index] To print out the third element of an array we would use: printf("%d", numbers[2]); numbers[0]numbers[1]numbers[2]numbers[3]numbers[4] 20154

Lab task #1 Create an algorithm and based on that a program User will input 5 numbers, that will be stored in an array After input, the following result will be printed on the screen: The list of the numbers that the user entered The smallest number entered The biggest number entered 20155

Improvements for the advanced Make the following changes to the code you wrote: Find the average, sum and product of the numbers entered Format Your output for better readability – try things like "%3d", "%3.2f" etc Allow the user to specify the number of elements that will be inputted

#define macros (preprocessor directive) #define macros are fulfilled before the code is compiled Works like “find and replace” The #define macros are placed right after the #include directives #define #define SIZE 7 #define TEXTFIELD_LEN 30 #define OPTIONS "settings.ini" Priority for now: avoid magic numbers, constants in code 20157

2-dimensional array (matrix) In this case we have a square matrix (both dimensions are equal) int array[5][5] array[0][0]array[0][1]array[0][2]array[0][3]array[0][4] array[1][0]array[1][1]array[1][2]array[1][3]array[1][4] array[2][0]array[2][1]array[2][2]array[2][3]array[2][4] array[3][0]array[3][1]array[3][2]array[3][3]array[3][4] array[4][0]array[4][1]array[4][2]array[4][3]array[4][4] 20158

Going through all of the elements #include int main(void) { int i, j, numArray[5][5]; for (i = 0; i < 5; i++) { for (j = 0; j < 5; j++) { numArray[i][j] = 0; } return 0; } 20159

Lab task #2 Create a 2-dimensional array for 10x10 multiplication table Avoid using magic numbers when declaring the array and limiting the loops The multiplication table will be stored in the array created →Use for() loops for this! The multiplication table is displayed from the array you generated →Use while() loops for this! Format your output for better visuals →Put line breaks at the right time →Use formatted output when printing numbers - %4d

Home task Modify your multiplication table, so that: The user can enter the size (width x length) Limit the size that can be entered based on what your program window can actually fit When the user inputs a size that’s out of bounds, ask again – use a do while() loop for this. You must be able to repeat the generation process without restarting the program. Create an algorithm with the state of lab task #2 (don’t include improvements from home task)