记录——《C Primer Plus （第五版）》第九章编程练习第四题

# include <stdio.h>

double harmonicMean(double, double);

int main(void)
{
double num1 = 23.4;
double num2 = 32.5;
double result;
result = HarmonicMean(num1, num2);
printf("The harmonic mean of the two numbers is %.4lf\n", result);

return 0;
}

double harmonicMean(double num1, double num2)
{
double result;
result = 1 / ((1/num1 + 1/num2) / 2);
return result;
}