and 
in the number system. This function returns the resistance of two resistors wired in parallel:
float ParallelResistance(float R1, float R2) {
return 1.0 / ( (1.0 / R1) + (1.0 / R2) );
}
Suppose R2 is 0. Then the expression 1.0 / ((1.0 / R1) + (1.0 / 0.0)) evaluates to 
, or 0, as expected of a short circuit. Similarly, if R2 is infinite, an open circuit, the result is R1. On pre-IEEE platforms, this program would be sprinkled with tests to avoid division by zero and with magic numbers such as 1.0E30 to represent (essentially) infinite resistance.
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