[C++] 纯文本查看 复制代码
// exec_mean.h -- exception classes for hmean(), gmean()
#include <iostream>
class bad_hmean
{
private:
double v1;
double v2;
public:
bad_hmean(double a = 0, double b = 0) : v1(a), v2(b){}
void mesg();
};
inline void bad_hmean::mesg()
{
std::cout << "hmean(" << v1 << ", " << v2 << "): "
<< "invalid arguments: a = -b\n";
}
class bad_gmean
{
public:
double v1;
double v2;
bad_gmean(double a = 0, double b = 0) : v1(a), v2(b){}
const char * mesg();
};
inline const char * bad_gmean::mesg()
{
return "gmean() arguments should be >= 0\n";
}
[C++] 纯文本查看 复制代码
//error4.cpp – using exception classes
#include <iostream>
#include <cmath> // or math.h, unix users may need -lm flag
#include "exec_mean.h"
// function prototypes
double hmean(double a, double b);
double gmean(double a, double b);
int main()
{
using std::cout;
using std::cin;
using std::endl;
double x, y, z;
cout << "Enter two numbers: ";
while (cin >> x >> y)
{
try { // start of try block
z = hmean(x, y);
cout << "Harmonic mean of " << x << " and " << y
<< " is " << z << endl;
cout << "Geometric mean of " << x << " and " << y
<< " is " << gmean(x, y) << endl;
cout << "Enter next set of numbers <q to quit>: ";
}// end of try block
catch (bad_hmean & bg) // start of catch block
{
bg.mesg();
cout << "Try again.\n";
continue;
}
catch (bad_gmean & hg)
{
cout << hg.mesg();
cout << "Values used: " << hg.v1 << ", "
<< hg.v2 << endl;
cout << "Sorry, you don't get to play any more.\n";
break;
} // end of catch block
}
cout << "Bye!\n";
// cin.get();
// cin.get();
return 0;
}
double hmean(double a, double b)
{
if (a == -b)
throw bad_hmean(a, b);
return 2.0 * a * b / (a + b);
}
double gmean(double a, double b)
{
if (a < 0 || b < 0)
throw bad_gmean(a, b);
return std::sqrt(a * b);
}