c11_01.cpp

it can help you know C++ souce program quckily

//***********************************
//**          C11_01.cpp           **
//         内联函数声明定义
//***********************************
#include <iostream >
using namespace std;

inline int isnumber(char  ch)		//内联函数声明并定义
{
	return (ch >= '0'&& ch <= '9')? 1 : 0;	//如果ch是数字则返回1，否则返回0值
}

int main( )
{
	char ch;
	while((ch=cin.get()) != '\n')	//读入一个字符赋给变量ch，并判断输入是否为回车键
	{
		if(isnumber(ch))			//调用内联函数isnumber
			cout << "the input is a number!\n";
		else
			cout << " the input is not a number!\n";
	}

	return 0;
}