1.cpp

能理解C++中运算符重载的需要性

#include <iostream.h>

int isnumber(char);

void main()
{
	char c;
	while((c=cin.get())!='\n')
	{
		if(isnumber(c))
			cout<<"you entered a digit\n";
		else
			cout<<"you entered a non-digit\n";
	}
}

int isnumber(char ch)
{
	return(ch>='0'&&ch<='9')?1:0;
}