main.cpp

来自「能计算如下表达式：x=3 y=4 z=x^2+sin(y)」· C++ 代码 · 共 55 行

#include ".\Expression.h"
#include<iostream>
#include<fstream>
using namespace std;
void main()
{	string str;
	Expression exp;
	char ch;
	cout << "键盘输入表达式按k/从文件输入表达式按f/退出按x：";
	cin >>ch;
	while(ch != 'x')
	{	
		while(ch !='x' && ch != 'k' && ch != 'f')
		{	
			cout << "键盘输入表达式按k/从文件输入表达式按f/退出按e：";
			cin >>ch;
		}
		if(ch == 'k')
		{	
			getchar(ch);
			cout <<"输入表达式:";
			getline(cin,str,'\n');	
			exp.setExpression(str);
			exp.parse();
			cout <<exp.getResult() <<endl;
			cout << "键盘输入表达式按k/从文件输入表达式按f/退出按x：";
			cin >>ch;
		}	
		if(ch == 'f')
		{
			string fname;
			char* pc = new char[100];
			cout<< "输入要打开的文件名:";
			cin>> fname;
			ifstream infile(fname.c_str());
			ofstream outfile("result.txt");
			while(infile)
			{
				infile.getline(pc,100);
				if(string(pc) != "")
				{
					exp.setExpression(pc);
					exp.parse();
					cout << pc <<endl <<exp.getResult() <<endl <<endl;
					outfile << pc <<endl <<exp.getResult() <<endl <<endl;
				}
			}
			cout << "键盘输入表达式按k/从文件输入表达式按f/退出按x：";
			cin >>ch;


		}
	}
}