63 lines
2.2 KiB
D
63 lines
2.2 KiB
D
import std.conv;
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import std.getopt;
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import std.stdio;
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import std.string;
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import quantities.runtime;
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import quantities.si;
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// Aaceleration limits (in g):
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const double lossOfConsciousness = 15.0;
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const double internalInjuries = 25.0;
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const double fatal = 40.0;
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const double puree = 100.0;
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const Acceleration g = 9.8 * metre / second / second; // about 35.3 km/h/s
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const Mass typicalHuman = 80 * kilogram;
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/++
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+ Prompt the user for a plausible number from stdin.
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+/
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double getVelocity() {
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string v = "";
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while (!isNumeric(v)) {
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write("How fast was The Flash going? Enter a speed, as km/h: ");
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v = readln().strip();
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}
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return to!double(v);
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}
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void main(string[] argv) {
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// Fetch a number from a cli argument, or prompt for one from stdin.
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double velocity = 0;
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auto args = getopt(argv,
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"velocity|v", "How fast The Flash was going", &velocity
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);
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if (args.helpWanted) {
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defaultGetoptPrinter("A stupid superhero physics calculator.", args.options);
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return;
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}
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writeln("Hello, welcome to the stupid superhero physics calculator.");
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if (!velocity) velocity = getVelocity();
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// v = vᵢ + at; vᵢ = 0, ∴ v = at, a = v/t
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Speed v = parseSI!Speed(format!"%s km/h"(velocity));
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Time t = 0.1 * second;
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Acceleration a = v / t;
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// F = ma
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Force f = typicalHuman * a;
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double accel_g = a / g;
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// Output some opinionated results.
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writefln("The Flash goes from stand-still to %s in a tenth of a second, thus accelerating at %.1f g.", "%.0f km/h".siFormat(v), accel_g);
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writefln("This would exert a force of %s on a typical human body.", "%.1f kN".siFormat(f));
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if (accel_g > puree) {
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writefln("Accelerating humans at over %.0f g requires hosing down afterwards.", puree);
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} else if (accel_g > fatal) {
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writefln("Accelerating humans at over %.0f g is usually fatal.", fatal);
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} else if (accel_g > internalInjuries) {
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writefln("Accelerating humans at over %.0f g results in injuries including internal bleeding.", internalInjuries);
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} else if (accel_g > lossOfConsciousness) {
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writefln("Accelerating humans at over %.0f g results in loss of consciousness.", lossOfConsciousness);
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}
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}
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