constrain()

Constrains a number to be within a range.
y = constrain(x, a, b);
x the number to constrain, all data types a the lower end of the range, all data types b the lower end of the range, all data types x — if x is between a and b
a — if x is less than a
b — if x is greater than b
sensVal = constrain(sensVal, 10, 150); // limits range of sensor values to between 10 and 150 
map()