In this course we will see how to use mathematical functions in your program.In fact, it can be really useful to calculate the square root of a number, or having it’s absolute value.
This is a list of basic operation:
| Operator | Code |
|---|---|
| Addition : + | int addition =5 + 5 // Return 10 into the variable |
| Subtraction : – | int subtracting =5 – 5 // Return 0 into the variable |
| Multiplication : * | int multiplication = 7*2; // return 14 into the variable |
| Divison : / | int division = 6/2; // return 3 in the variable |
| Modulo : % | int modulo =7 % 5 // return 2 in the variable |
| Operator | Code |
|---|---|
| Is to not equal to : != | if (5 !=8) { // Your code }; //Here we enter in the loop because 5 is different to 8. |
| Smaller than: < | if (2<3) { // Your code }; // We enter in the loop because 2 is smaller than 3. |
| Smaller or equal to : <= | if (2<=2) { // Your code }; //Here we enter in the loop because 2 is smaller or equal to 3. |
| Equal to : == | if (6==6) { // Your code }; // Here we enter in the loop because 6 is equals to 6. |
| Bigger than : > | if (9>1) { // Your code }; // Here we enter in the loop because 9 is bigger than 1 |
| Bigger or equal to : >= | if (9>=9) { // Your code }; // Here we enter in the loop because 9 is bigger or equal to 9. |
| Opérateur | Code |
|---|---|
| Logical NOT : ! | if (!x) { // if x is False Your code } |
| Logical AND : && | if (5==5 && 2==2) { // The both conditions are true therefore we enter in the code. } |
| Logical OR : || | if (3==3 || 4==4) { // We enter in this code because one of the two equalities is true. }; |
The function absolute value is used to be sure that a number is positive or null. This function can be also used to transform a negative number to a positive one.
The abs() function take in parameter a number positive or negative and return the same number in positive:
abs(number);abs(-5); // return 5abs(0); // return 0max(x,y);max(23,2);// Return 23In your program, you may need to retrieve a value of a sensor or have a minimum value in case if the value of the sensor is to low.
Here is an example:
value_sensor =max(photoresistor, 20)// Take the value of the photoresistor if this value is bigger than 20 In this example, the variable value_sensor take the value of the photoresistor if this the value is bigger than 20, otherwise it will take 20.
The minimum function is the reverse of the maximum function, that ‘s mean that the function takes two values and return the smallest one.
min(x,y);Here is an example with the numbers : x=23, y=2:
min(23,2);// Return 2The function return 2. X and Y can have a different type: string, int, float…
In a program, you can also need to retrieve a value from a sensor or a maximum value in case if the value of the sensor is too high.
Here is an example:
value_sensor =min(photoresistor, 20)// Take the value of the photoresistor if inferior to 20In this example, the variable value_sensor takes the value of the photoresistor if it’s lower than 20, otherwise it will take 20.
The function sqrt is used to have the square root of a number:
sqrt(x) // Square root of the number xThe function sqrt() return a double.
Here is an example with the number 25:
sqrt(25) // The square root of 25 return 5.00
We will see now how the cosine, sine and tangent works:
The cosine function takes in parameter an angle in radian and return a value between 1 and -1:
cos(rad); // return a value between 1 and -1 The function takes in parameter a float and return a double.
Here is an example with the cosine with an angle of 90°:
cos(90); // return the value -0.45The sine function takes in parameter an angle in radian and return a value between 1 to -1:
sin(rad); // return the value between 1 and -1. The function takes in parameter a float and return a double.
Here is an example with the sine with an angle of 90°:
sin(90); // return the value 0.89The function tangent takes in parameter an angle in radian and return a value between minus infinite to infinite:
tan(rad); // return a value between minus infinite and infinite
tan(0); // return 0.00