C++ equivalent of Processing's map() function

问题

Processing has a function map that

Re-maps a number from one range to another.

For example

int ans = map(5, 0, 10, 0, 100);

ans will be 50 as 5 is halfway between 0 and 10 and halfway between 0 and 100 is 50.

If there is no built in function how would I write my own one?

回答1:

Processing is open source, and you can view the source for the map() function here.

Specifically, this is the line you care about:

float outgoing =
  start2 + (stop2 - start2) * ((value - start1) / (stop1 - start1));

来源：https://stackoverflow.com/questions/43683041/c-equivalent-of-processings-map-function