public class PercentChangeProgram {
public static double percentChange(double x, double y) {
return ((y - x) / Math.abs(x)) * 100.0;
}
public static String describeChange(double x, double y) {
double pct = percentChange(x, y);
if (pct > 0) {
return String.format(
"From %.1f to %.1f is a %.2f%% increase (+%.2f%%)",
x, y, pct, pct
);
} else if (pct < 0) {
return String.format(
"From %.1f to %.1f is a %.2f%% decrease (%.2f%%)",
x, y, Math.abs(pct), pct
);
} else {
return String.format(
"From %.1f to %.1f is no change",
x, y
);
}
}
public static void main(String[] args) {
System.out.println(describeChange(-80.0, 120.0));
System.out.println(describeChange(120.0, 30.0));
}
}
/*
run:
From -80.0 to 120.0 is a 250.00% increase (+250.00%)
From 120.0 to 30.0 is a 75.00% decrease (-75.00%)
*/
