9. Programming (4) Flashcards
Why are functions useful?
- They let us split the code into smaller subsections which are easier to understand.
- Let us make units of code (our functions) that can easily be reused.
How to define a function called myFunction?
int myFunction(int parameter1, float parameter2) { // write the function body in here return intVal; } Where you can have as many or few parameters as you want and the return value has to be of the same type as the header.
How to write a function that will add 2 numbers?
int add(int number1, int number2) { int answer; answer = number1 + number2; return answer; }
Can you show the newly defined add function being used?
int sum;
sum = add(4,7); // sum is set to 11
sum = add(5,6,7); // ERROR - needs 2 parameters.
How to define a function that will flash an LED?
void flash(int interval) { digitalWrite(LEDpin, HIGH); delay(interval); digitalWrite(LEDpin, LOW); delay(interval); return; // this line is optional because no return value }
Example usages of flash function?
flash(1000); // a slow 1 sec flash
flash(100); // much faster
flash(); // ERROR - need a parameter
What does void return type mean?
No return statement is required.
what can the for loop be used for?
repeating an action a number of times: for (A; B; C) { // things to be repeated }
what are A B and C in the above question?
- A is the variable initialisation for the loop
- B is the continuation condition
- C is the variable update
how does:
int x = 0;
for (int i=0; i
int i=0 - this initialises an integer variable called i to be 0.
i
how to work out factorial 5 using a for loop?
int x = 1;
for (int i=1; i
what does for(; ;) do?
creates an infinite loop
how to get out of an infinite loop?
use break keyword; very useful if combined with an if statement.
what is a better way of setting up a loop which stops when something happens?
the do.. while() loop does something(s) as long as a condition holds. do { // things to repeat } while(condition)
what are the numbers for false and true?
false - 0
true - 1