mathoptr.h

一个不带界面的计算器

//MathOptr.h是calculator的头文件
#include<iostream.h>
#include<math.h>
#ifndef MATHOPTR_H
#define MATHOPTR_H
class MathOptr
{
private:
	char Op;
	int InputPrecedence;					//读入优先级
	int StackPrecedence;					//栈优先级
public:
	MathOptr(char ch=' ');					//给读入的运算附和左右括号配备优先级
	int operator>=(MathOptr a)const;		//操作符>=重载
	void Evaluate(Stack<double>& Opnd);		//执行从运算符栈弹出的运算符optr所要求的运算
	int  AWriteWrongToFile(char *pFileName);//数据类型不符时出错
	char GetOp(void)						//返回运算符
	{
		return Op;
	}
};
#endif
///////////////////////////////////////////////////////////////////////////////
//类的成员函数的定义
MathOptr::MathOptr(char ch)					
{
	Op=ch;
	switch(Op)
	{
		case '+':
        case '-':InputPrecedence=1;
			     StackPrecedence=1;
				 break;
		case '*':
		case '%':
		case '/':InputPrecedence=2;
			     StackPrecedence=2;
				 break;
		case '^':InputPrecedence=4;
			     StackPrecedence=3;
				 break;
		case '(':InputPrecedence=5;
			     StackPrecedence=-1;
				 break;
		case ')':InputPrecedence=0;
			     StackPrecedence=0;
				 break;
	}
}

int MathOptr::operator >=(MathOptr a)const
{
	return(StackPrecedence>=a.InputPrecedence);
}

void MathOptr::Evaluate(Stack<double>& Opnd)
{
	double Opnd1=Opnd.Pop();
	double Opnd2=Opnd.Pop();
	switch(Op)
	{
		case '+':Opnd.Push(Opnd1+Opnd2);
				 break;
		case '-':Opnd.Push(Opnd2-Opnd1);
			     break;
		case '*':Opnd.Push(Opnd1*Opnd2);
	             break;
		case '/':
				 if(!Opnd1)
				 {
					cout<<"ERROR IN INFIX NOTATION !\n";
					AWriteWrongToFile("output.txt");
				 }
				 else Opnd.Push(Opnd2/Opnd1);
				 break;
		case '%':
				 if(Opnd1!=(int)Opnd1||Opnd2!=(int)Opnd2)
				 {
					 cout<<"ERROR IN INFIX NOTATION !\n";
					 AWriteWrongToFile("output.txt");
				 }
				 else Opnd.Push((int)Opnd2%(int)Opnd1);
				 break;
		case '^':
				 if(Opnd1!=(int)Opnd1)
				 {
					 cout<<"ERROR IN INFIX NOTATION !\n";
					 AWriteWrongToFile("output.txt");
				 }
				 else Opnd.Push(pow(Opnd2,Opnd1));
				 break;
	}
}
int MathOptr:: AWriteWrongToFile(char *pFileName)
{
	FILE *fp;
	if( (fp = fopen( pFileName, "a+" )) == NULL )
	{
		printf(" can not open file ! \n");

		return 0;

	}
	fprintf( fp, "ERROR IN INFIX NOTATION !\n");	
	fclose( fp );
	return 1;

}