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Utility
Math
This library performs all types of calculations including min/max, absolute value and the square root of a number. Users can also constrain a number within a range, re-map a number from one range to another, and calculate the value of a number raised to a power.
min
- Description
- Compares two values, returns the smaller one.
- Syntax
- min(x, y)
- Parameters
- x: The first number, any data type
y: The second number, any data type - Returns
- The smaller of the two parameter values.
max
- Description
- Compares two values, returns the larger one.
- Syntax
- max(x, y)
- Parameters
- x: The first number, any data type
y: The second number, any data type - Returns
- The larger of the two parameter values.
abs
- Description
- Computes and returns the absolute value of a number.
- Syntax
- abs(x)
- Parameters
- x: The number to be converted
- Returns
- If x is greater than or equal to 0, returns x; if less than 0, returns -x.
constrain
- Description
- Constrains a number to be within a range.
- Syntax
- constrain(x, a, b)
- Parameters
- x: The number to constrain, all data types
a: The lower end of the range, all data types
b: The upper end of the range, all data types - Returns
- If x is between a and b, returns x; if x is less than a, returns a; if x is greater than b, returns b.
map
- Description
- Re-maps a number from one range to another. For example, when the value is 5 within the range of 0 to 10, it is re-mapped to 50 in the range of 0 to 100.
- Syntax
- map(value, fromLow, fromHigh, toLow, toHigh)
- Parameters
- value: The number to map
fromLow: The lower bound of the value's current range
fromHigh: The upper bound of the value's current range
toLow: The lower bound of the value's target range
toHigh: The upper bound of the value's target range - Returns
- The value after mapping
pow
- Description
- Calculates power (exponential).
- Syntax
- pow(base, exponent)
- Parameters
- base: Any value; (float)
exponent: The power to which the base is raised (float) - Returns
- The result of the exponentiation (double)
sqrt
- Description
- Calculates the square root of a number.
- Syntax
- sqrt(x)
- Parameters
- x: The number, any value
- Returns
- Double, the number's square root.
Sample Program
Sample using constrain and pow.
#include <Arduino.h>
void setup(){
Serial.begin(9600);
while(!Serial.available()); //key wait
Serial.read(); // dummy read
}
void loop(){
Serial.println("Calculate the area of a circle ");
Serial.println("Input value 0-9");
while(!Serial.available());
int d = Serial.read();
d = constrain(d - 0x30, 0, 9); //convert from ASCII to numeric, and remove error value
Serial.print(d);
Serial.print(" x ");
Serial.print(d);
Serial.print(" x 3.14 = ");
Serial.println(pow(d, 2) * PI);
}