objective-c第二十一章课后练习题

//  ViewController.m//  Fraction_Calculator////  Created by new on 15/6/7.//  Copyright (c) 2015年  All rights reserved.//#import "ViewController.h"@interface ViewController ()@end@implementation ViewController{    char op;    int numberOps;    int currentNumber;//输入中的数字    BOOL firstOperand,isNumerator;//跟踪输入的是第一个分数和第二个分数，以及输入的是分子还是分母；    BOOL isNegative,writingDigit;//跟踪输入的是否是负数，以及书写位数；    Calculator *myCalculator;    NSMutableString *displayString;}@synthesize display;-(void)viewDidLoad{    //覆盖应用程序载入的自定义方法    firstOperand=YES;    isNumerator=YES;        isNegative=NO;    writingDigit=NO;    numberOps=0;    displayString=[NSMutableString stringWithCapacity:40];    myCalculator=[[Calculator alloc]init];}-(void)errorOutDisplay{    [myCalculator clear];    [displayString setString:@"Error!"];    [display setText:displayString];}-(void)processDight:(int)digit{    if (isNegative)        currentNumber=currentNumber*10-digit;    else        currentNumber=currentNumber*10+digit;    if(!writingDigit)        writingDigit=YES;    [displayString appendString:[NSString stringWithFormat:@"%i",digit]];    display.text=displayString;}-(IBAction)clickDigit:(UIButton *)sender{    int digit;    digit=(int)sender.tag;    [self processDight:digit];}-(void)processOp:(char)theOp{    NSString *opStr;    [self storeFracPart];    numberOps++;    if (numberOps>1) {        NSLog(@"------%i",numberOps);        [myCalculator performOperation:op];        myCalculator.operand1.numerator=myCalculator.accumulator.numerator;        myCalculator.operand1.denominator=myCalculator.accumulator.denominator;    }    if (writingDigit==NO && theOp=='-') {        isNegative=YES;        [displayString setString:[displayString stringByAppendingString:@"-"]];        [display setText:displayString];        return ;    }    op=theOp;    switch (theOp) {        case '+':            opStr=@"+";            break;        case '-':            opStr=@"-";            break;        case '*':            opStr=@"∞";            break;        case '/':            opStr=@"÷";            break;    }    //[self storeFracPart];    firstOperand=NO;    isNumerator=YES;    writingDigit=NO;    isNegative=NO;        [displayString appendString:opStr];    display.text=displayString;}-(void)storeFracPart{    if (firstOperand)    {        if (isNumerator)        {            myCalculator.operand1.numerator=currentNumber;            myCalculator.operand1.denominator=1;        }        else        {            if (currentNumber==0)                [self errorOutDisplay];            myCalculator.operand1.denominator=currentNumber;        }    }    else if (isNumerator)    {        myCalculator.operand2.numerator=currentNumber;        myCalculator.operand2.denominator=1;    }    else    {        if (currentNumber==0)            [self errorOutDisplay];        myCalculator.operand2.denominator=currentNumber;        firstOperand=YES;    }    currentNumber=0;}-(IBAction)clickOver{    [self storeFracPart];    isNumerator=NO;    isNegative=NO;        [displayString appendString:@"/"];    display.text=displayString;}//算术操作键-(IBAction)clickPlus{    [self processOp:'+'];}-(IBAction)clickMinus{    [self processOp:'-'];}-(IBAction)clickMultiply{    [self processOp:'*'];}-(IBAction)clickDivide{    [self processOp:'/'];}//Misc键-(IBAction)clickEquals{       if (firstOperand==NO) {        [self storeFracPart];        [myCalculator performOperation:op];        [displayString appendString:@"="];        [displayString appendString:[myCalculator.accumulator convertToString]];        display.text=displayString;                currentNumber=0;        isNumerator=YES;        firstOperand=YES;                numberOps=0;        [displayString setString:@""];    }}-(IBAction)clickClear{            numberOps=0;    isNumerator=YES;    firstOperand=YES;    currentNumber=0;    [myCalculator clear];    [displayString setString:@""];    display.text=displayString;}-(IBAction)Convert{    if(firstOperand && isNumerator &&!currentNumber)    {        [displayString setString:[NSString stringWithFormat:@"%g",[myCalculator.accumulator convertToNum]]];        [display setText:displayString];            }}- (void)viewDidUnLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

//  ViewController.h//  Fraction_Calculator////  Created by new on 15/6/7.//  Copyright (c) 2015年 All rights reserved.//#import <UIKit/UIKit.h>#import "Calculator.h"@interface ViewController : UIViewController@property(strong,nonatomic)IBOutlet UILabel *display;-(void)processDight:(int)digit;-(void)processOp:(char)theOp;-(void)storeFracPart;-(void)errorOutDisplay;//数字键-(IBAction)clickDigit:(UIButton*)sender;//算术操作键-(IBAction)clickPlus;-(IBAction)clickMinus;-(IBAction)clickMultiply;-(IBAction)clickDivide;//Misc键-(IBAction)clickOver;-(IBAction)clickEquals;-(IBAction)clickClear;-(IBAction)Convert;@end