【iOS】计算器实现
仿写iOS的计算器，使用了MVC模式和masonry库。
绘制界面
- 循环建立button，统一设置属性，添加约束。
- 将括号按钮的tag设成100+，运算符按钮的tag设成200+，数字按钮的tag设成300+，用于之后分类。
- 设置不同按钮的颜色。
- 将AC，等于和小数点这种特殊按钮赋给mainView的属性。
- MainView声明一个数组属性，将除上面三个特殊按钮之外的按钮全部添加到数组里。
- 在按钮上方添加一个UITextField，关掉它的用户交互。
MainView.h
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
@interface MainView : UIView
@property (nonatomic, strong) NSArray* operArray;
@property (nonatomic, strong) NSMutableArray* buttonArray;
@property (nonatomic, strong) UITextField* calculation;
@property (nonatomic, strong) UIButton* ACButton;
@property (nonatomic, strong) UIButton* equalButton;
@property (nonatomic, strong) UIButton* pointButton;
- (void) initView;
@end
NS_ASSUME_NONNULL_END
MainView.m
#import "MainView.h"
#import "Masonry.h"
#define SIZE 85
#define CalculationWidth 375
@implementation MainView
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
// Drawing code
}
*/
- (void) initView {
self.backgroundColor = [UIColor blackColor];
[self creatOperArray];
self.buttonArray = [[NSMutableArray alloc] init];
self.calculation = [[UITextField alloc] init];
self.calculation.backgroundColor = [UIColor blackColor];
self.calculation.textColor = [UIColor whiteColor];
self.calculation.textAlignment = NSTextAlignmentRight;
self.calculation.font = [UIFont systemFontOfSize:60];
self.calculation.userInteractionEnabled = NO;
[self addSubview:self.calculation];
[self.calculation mas_makeConstraints:^(MASConstraintMaker *make) {
make.bottom.equalTo(self).offset(-600);
make.width.equalTo(@CalculationWidth);
}];
for (int i = 0; i < 4; i++) {
for (int j = 0; j < 4; j++) {
UIButton* button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.titleLabel.font = [UIFont systemFontOfSize:42];
button.layer.cornerRadius = SIZE / 2;
[self addSubview:button];
[button mas_makeConstraints:^(MASConstraintMaker *make) {
make.bottom.equalTo(self).offset(-(70 + (SIZE + 15) * (i + 1)));
make.left.equalTo(self).offset(3 + (SIZE + 15) * j);
make.size.equalTo(@SIZE);
}];
if (i == 3 && j < 3) {
button.backgroundColor = [UIColor grayColor];
[button setTitle:self.operArray[i + j + 1] forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
button.tag = 100 + j;
if (j == 0) {
_ACButton = button;
} else {
[self.buttonArray addObject:button];
}
} else if (j == 3) {
button.backgroundColor = [UIColor colorWithRed:251.0f / 255.0f green:151.0f / 255.0f blue:15.0f / 255.0f alpha:1];
[button setTitle:self.operArray[i] forState:UIControlStateNormal];
[button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
button.tag = 200 + i;
[self.buttonArray addObject:button];
} else {
button.backgroundColor = [UIColor colorWithRed:0.2 green:0.2 blue:0.2 alpha:1];
NSString* title = [NSString stringWithFormat:@"%d", j + 3 * i + 1];
[button setTitle:title forState:UIControlStateNormal];
[button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
button.tag = 300 + i * 3 + j;
[self.buttonArray addObject:button];
}
}
}
for (int i = 0; i < 3; i++) {
UIButton* button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.titleLabel.font = [UIFont systemFontOfSize:42];
button.layer.cornerRadius = SIZE / 2;
[button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
[self addSubview:button];
if (i == 0) {
[button mas_makeConstraints:^(MASConstraintMaker *make) {
make.bottom.equalTo(self).offset(-70);
make.left.equalTo(self).offset(0);
make.width.equalTo(@(SIZE * 2 + 15));
make.height.equalTo(@SIZE);
}];
[button setTitle:@"0 " forState:UIControlStateNormal];
button.backgroundColor = [UIColor colorWithRed:0.2 green:0.2 blue:0.2 alpha:1];
button.tag = 310;
[self.buttonArray addObject:button];
} else {
[button mas_makeConstraints:^(MASConstraintMaker *make) {
make.bottom.equalTo(self).offset(-70);
make.left.equalTo(self).offset(200 + (SIZE + 15) * (i - 1));
make.size.equalTo(@SIZE);
}];
if (i == 1) {
[button setTitle:@"." forState:UIControlStateNormal];
button.backgroundColor = [UIColor colorWithRed:0.2 green:0.2 blue:0.2 alpha:1];
button.tag = 311;
self.pointButton = button;
} else {
[button setTitle:@"=" forState:UIControlStateNormal];
button.backgroundColor = [UIColor colorWithRed:251.0f / 255.0f green:151.0f / 255.0f blue:15.0f / 255.0f alpha:1];
button.tag = 400;
_equalButton = button;
}
}
}
}
- (void) creatOperArray {
NSArray* array = [[NSArray alloc] initWithObjects:@"+", @"-", @"×", @"÷", @"AC", @"(", @")", nil];
self.operArray = array;
}
@end
添加事件
- MVC模式要求我们在MainViewController里实现并添加事件。
- 我们在MainViewController例调用MainView的属性，为AC，等于和小数点这种特殊按钮单独添加事件。
[self.mainView.ACButton addTarget:self action:@selector(pressAcButton:) forControlEvents:UIControlEventTouchUpInside];
[self.mainView.equalButton addTarget:self action:@selector(pressEqualButton:) forControlEvents:UIControlEventTouchUpInside];
[self.mainView.pointButton addTarget:self action:@selector(pressPiontButton:) forControlEvents:UIControlEventTouchUpInside];
- 遍历MainView中储存普通按钮的数组，为它们添加一个总的事件。
for (UIButton* button in self.mainView.buttonArray) {
[button addTarget:self action:@selector(pressButton:) forControlEvents:UIControlEventTouchUpInside];
}
- 在这个总事件里，使用按钮的tag值进行分类，调用不同的事件。
- (void) pressButton:(UIButton*)sender {
if (sender.tag / 100 == 1) {
[self pressBracButton:sender];
} else if (sender.tag / 100 == 2) {
[self pressOperButton:sender];
} else if (sender.tag / 100 == 3) {
[self pressNumberButton:sender];
}
}
- 实现这些事件。
限制输入
在一定程度上限制用户的输入，保证算术式的正确。
- 为每种按钮设置BOOL类型或NSInteger类型的属性，用于判断此按钮是否生效。每次用户触发点击事件后，先通过这些属性判断此次点击是否有效。若有效，则输入新数据；若无效，则跳过。
@property (nonatomic, assign) NSInteger rightBracLimit;
@property (nonatomic, assign) BOOL lefBracLimit;
@property (nonatomic, assign) BOOL OperLimit;
@property (nonatomic, assign) BOOL NumLimit;
@property (nonatomic, assign) BOOL pointLimitByNum;
@property (nonatomic, assign) BOOL pointLimitByOper;
@property (nonatomic, assign) BOOL OperLimitJJ;
- 初始化这些属性，每种按钮在开始时是否有效是固定的，我们只需要将它们列出来。
// 设置按钮初始限制状态
_rightBracLimit = 0;
_lefBracLimit = YES;
_NumLimit = YES;
_OperLimit = NO; // 乘除
_pointLimitByNum = NO;
_pointLimitByOper = YES;
_OperLimitJJ = YES; // 加减
- 某个按钮的点击事件生效后，每种按钮是否有效也是固定的，我们一样将它们列出来。（以数字按钮为例）
- (void) pressNumberButton:(UIButton*)sender {
if (self.NumLimit) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = nil;
if ([newChar isEqual:@"0 "]) {
newCalculation = [NSString stringWithFormat:@"%@0", oldCalculation];
} else {
newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
}
self.mainView.calculation.text = newCalculation;
// 设置按钮限制状态
_lefBracLimit = NO;
if (_rightBracLimit < 0) {
_rightBracLimit = -_rightBracLimit;
}
_OperLimit = YES;
_OperLimitJJ = YES;
if (_pointLimitByOper) {
_pointLimitByNum = YES;
}
}
}
- 右括号和小数点的限制比较特殊。
右括号使用NSInteger类型，记录输入左括号的数量。输入一个左括号，我们是这个属性值加一，输入一个右括号减一。我们限制只有这个属性的值大于0，点击才能生效。如果输入某个非右括号的符号，我们将这个值改为负数以限制错误输入。（下为括号的点击事件）
// 处理括号
- (void) pressBracButton:(UIButton*)sender {
if (sender.tag == 101) {
if (_lefBracLimit) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
self.mainView.calculation.text = newCalculation;
if (_rightBracLimit < 0) {
_rightBracLimit = -_rightBracLimit;
}
_rightBracLimit++;
_OperLimit = NO;
_NumLimit = YES;
_OperLimitJJ = YES;
_pointLimitByNum = NO;
_pointLimitByOper = YES;
}
} else {
if (_rightBracLimit > 0) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
self.mainView.calculation.text = newCalculation;
_rightBracLimit = _rightBracLimit - 1;
_lefBracLimit = NO;
_NumLimit = NO;
_OperLimit = YES;
_pointLimitByNum = NO;
_pointLimitByOper = YES;
_OperLimitJJ = YES;
}
}
}
小数点使用两个属性限制。一个属性限制小数点前存在数字，一个属性限制两个有效的小数点之间存在一个有效运算符，保证一个数字只有一个小数点。
MainViewController全部代码
MainViewController.h
#import <UIKit/UIKit.h>
#import "MainView.h"
#import "CalculatorModel.h"
NS_ASSUME_NONNULL_BEGIN
@interface MainViewController : UIViewController
@property (nonatomic, strong) MainView* mainView;
@property (nonatomic, strong) CalculatorModel* model;
@property (nonatomic, assign) NSInteger rightBracLimit;
@property (nonatomic, assign) BOOL lefBracLimit;
@property (nonatomic, assign) BOOL OperLimit;
@property (nonatomic, assign) BOOL NumLimit;
@property (nonatomic, assign) BOOL pointLimitByNum;
@property (nonatomic, assign) BOOL pointLimitByOper;
@property (nonatomic, assign) BOOL OperLimitJJ;
@end
NS_ASSUME_NONNULL_END
MainViewController.m
#import "MainViewController.h"
#define MAXSIZE 100
@interface MainViewController ()
@end
@implementation MainViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
[self createView];
[self createModel];
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
- (void) createView {
self.mainView = [[MainView alloc] initWithFrame:self.view.bounds];
[self.mainView initView];
[self.view addSubview:self.mainView];
// 设置按钮初始限制状态
_rightBracLimit = 0;
_lefBracLimit = YES;
_NumLimit = YES;
_OperLimit = NO;
_pointLimitByNum = NO;
_pointLimitByOper = YES;
_OperLimitJJ = YES;
for (UIButton* button in self.mainView.buttonArray) {
[button addTarget:self action:@selector(pressButton:) forControlEvents:UIControlEventTouchUpInside];
}
[self.mainView.ACButton addTarget:self action:@selector(pressAcButton:) forControlEvents:UIControlEventTouchUpInside];
[self.mainView.equalButton addTarget:self action:@selector(pressEqualButton:) forControlEvents:UIControlEventTouchUpInside];
[self.mainView.pointButton addTarget:self action:@selector(pressPiontButton:) forControlEvents:UIControlEventTouchUpInside];
}
- (void) pressButton:(UIButton*)sender {
if (sender.tag / 100 == 1) {
[self pressBracButton:sender];
} else if (sender.tag / 100 == 2) {
[self pressOperButton:sender];
} else if (sender.tag / 100 == 3) {
[self pressNumberButton:sender];
}
}
// 处理括号
- (void) pressBracButton:(UIButton*)sender {
if (sender.tag == 101) {
if (_lefBracLimit) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
self.mainView.calculation.text = newCalculation;
if (_rightBracLimit < 0) {
_rightBracLimit = -_rightBracLimit;
}
_rightBracLimit++;
_OperLimit = NO;
_NumLimit = YES;
_OperLimitJJ = YES;
_pointLimitByNum = NO;
_pointLimitByOper = YES;
}
} else {
if (_rightBracLimit > 0) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
self.mainView.calculation.text = newCalculation;
_rightBracLimit = _rightBracLimit - 1;
_lefBracLimit = NO;
_NumLimit = NO;
_OperLimit = YES;
_pointLimitByNum = NO;
_pointLimitByOper = YES;
_OperLimitJJ = YES;
}
}
}
- (void) pressOperButton:(UIButton*)sender {
if (sender.tag > 201) {
[self pressOperButtonCC:sender];
} else {
[self pressOperButtonJJ:sender];
}
}
// C:乘 C:除
- (void) pressOperButtonCC:(UIButton*)sender {
if (_OperLimit) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
self.mainView.calculation.text = newCalculation;
_OperLimit = NO;
_OperLimitJJ = NO;
_NumLimit = YES;
_lefBracLimit = YES;
if (_rightBracLimit > 0) {
_rightBracLimit = -_rightBracLimit;
}
_pointLimitByOper = YES;
_pointLimitByNum = NO;
}
}
// J:加 J:减
- (void) pressOperButtonJJ:(UIButton*)sender {
if (_OperLimitJJ) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
self.mainView.calculation.text = newCalculation;
_OperLimit = NO;
_OperLimitJJ = NO;
_NumLimit = YES;
_lefBracLimit = YES;
if (_rightBracLimit > 0) {
_rightBracLimit = -_rightBracLimit;
}
_pointLimitByOper = YES;
_pointLimitByNum = NO;
}
}
- (void) pressNumberButton:(UIButton*)sender {
if (self.NumLimit) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = nil;
if ([newChar isEqual:@"0 "]) {
newCalculation = [NSString stringWithFormat:@"%@0", oldCalculation];
} else {
newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
}
self.mainView.calculation.text = newCalculation;
_lefBracLimit = NO;
if (_rightBracLimit < 0) {
_rightBracLimit = -_rightBracLimit;
}
_OperLimit = YES;
_OperLimitJJ = YES;
if (_pointLimitByOper) {
_pointLimitByNum = YES;
}
}
}
- (void) pressPiontButton:(UIButton*)sender {
if (_pointLimitByNum && _pointLimitByOper) {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSString* newCalculation = [NSString stringWithFormat:@"%@%@", oldCalculation, newChar];
self.mainView.calculation.text = newCalculation;
_OperLimit = NO;
_NumLimit = YES;
_lefBracLimit = NO;
if (_rightBracLimit > 0) {
_rightBracLimit = -_rightBracLimit;
}
_pointLimitByNum = NO;
_pointLimitByOper = NO;
_OperLimitJJ = NO;
}
}
- (void) pressAcButton:(UIButton*)sender {
self.mainView.calculation.text = nil;
// 设置按钮初始限制状态
_rightBracLimit = 0;
_lefBracLimit = YES;
_NumLimit = YES;
_OperLimit = NO;
_pointLimitByNum = NO;
_pointLimitByOper = YES;
_OperLimitJJ = YES;
}
- (void) pressEqualButton:(UIButton*)sender {
NSString* oldCalculation = self.mainView.calculation.text;
NSString* newChar = sender.titleLabel.text;
NSMutableString* newCalculation = [NSMutableString stringWithFormat:@"%@%@", oldCalculation, newChar];
for (int i = 0; i < oldCalculation.length; i++) {
NSString* s = [oldCalculation substringWithRange:NSMakeRange(i, 1)];
if ([s isEqualToString:@"÷"]) {
[newCalculation replaceCharactersInRange:NSMakeRange(i, 1) withString:@"/"];
} else if ([s isEqualToString:@"×"]) {
[newCalculation replaceCharactersInRange:NSMakeRange(i, 1) withString:@"*"];
}
}
if ([self isCalculationTrue:newCalculation]) {
[self.model Calculat:newCalculation];
} else {
self.mainView.calculation.text = @"error";
}
// 设置按钮初始限制状态
_rightBracLimit = 0;
_lefBracLimit = NO;
_NumLimit = YES;
_OperLimit = YES;
_pointLimitByNum = NO;
_pointLimitByOper = YES;
_OperLimitJJ = YES;
}
- (BOOL) isCalculationTrue:(NSString*)calculation {
if ([calculation containsString:@"e"]) {
return NO;
} else if ([calculation containsString:@"r"]) {
return NO;
} else if ([calculation containsString:@"o"]) {
return NO;
} else if (_rightBracLimit) {
return NO;
} else {
NSInteger index = calculation.length - 2;
NSString* s = [calculation substringWithRange:NSMakeRange(index, 1)];
if ([s isEqualToString:@"+"]) {
return NO;
} else if ([s isEqualToString:@"-"]) {
return NO;
} else if ([s isEqualToString:@"*"]) {
return NO;
} else if ([s isEqualToString:@"/"]) {
return NO;
} else {
return YES;
}
}
}
- (void) createModel {
self.model = [[CalculatorModel alloc] init];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(upAnswer:) name:@"answer" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(upError) name:@"error" object:nil];
}
- (void) upAnswer:(NSNotification*)notification {
NSDictionary* answer = notification.userInfo;
self.mainView.calculation.text = answer[@"Value"];
}
- (void) upError {
self.mainView.calculation.text = @"error";
}
@end
运算
首先我需要模拟一个栈。我是建立一个对象CalculatorStack。
CalculatorStack.h
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#define MAXSIZE 100
NS_ASSUME_NONNULL_BEGIN
@interface CalculatorStack : NSObject
{
CGFloat _data[MAXSIZE];
NSInteger _top;
}
- (void) Push:(CGFloat)element;
- (CGFloat) Pop;
- (CGFloat) GetTop;
- (void) initStack;
@end
NS_ASSUME_NONNULL_END
CalculatorStack.m
#import "CalculatorStack.h"
@implementation CalculatorStack
- (id) init {
if (self = [super init]) {
_top = -1;
}
return self;
}
- (void) initStack {
_top = -1;
}
- (void) Push:(CGFloat)element {
if (_top == 99) {
return;
}
_data[++_top] = element;
}
- (CGFloat) Pop {
if (_top == -1) {
return 0;
}
return _data[_top--];
}
- (CGFloat) GetTop {
if (_top == -1) {
return 0;
}
return _data[_top];
}
@end
在Model中计算，我使用后缀表达式。
- 建立两个栈，一个存数字，一个存运算符。
- 向运算符栈压入一个“=”，主要用于计算第一个运算符的优先级。
- 从左向右扫描表达式。
- 遇到数字存入数字栈。
- 遇到运算符，与栈顶运算符比较优先级。优先级大，压入栈中；优先级小，计算栈顶运算符；优先级相等，证明匹配到“()”，弹出栈顶运算符。
CalculatorModel.h
#import <Foundation/Foundation.h>
#import "CalculatorStack.h"
NS_ASSUME_NONNULL_BEGIN
@interface CalculatorModel : NSObject
{
CalculatorStack* _Num;
CalculatorStack* _Oper;
}
- (void) Calculat:(NSString*)calculationString;
@end
NS_ASSUME_NONNULL_END
CalculatorModel.m
#import "CalculatorModel.h"
int cmp[7][7] = {
{ 2, 2, 1, 1, 1, 2, 2 },
{ 2, 2, 1, 1, 1, 2, 2 },
{ 2, 2, 2, 2, 1, 2, 2 },
{ 2, 2, 2, 2, 1, 2, 2 },
{ 1, 1, 1, 1, 1, 3, 0 },
{ 2, 2, 2, 2, 0, 2, 2 },
{ 1, 1, 1, 1, 1, 0, 3 } };
char op[7] = {'+', '-', '*', '/', '(', ')', '='};
@implementation CalculatorModel
- (id) init {
if (self = [super init]) {
_Num = [[CalculatorStack alloc] init];
_Oper = [[CalculatorStack alloc] init];
}
return self;
}
- (BOOL) inCalculator:(char)ch {
if (ch == '+' || ch == '*' || ch == '/' || ch == '-' || ch == '(' || ch == ')' || ch == '=') {
return YES;
}
return NO;
}
- (char) CompareOper1:(char)oper1 AndOper2:(char)oper2 {
int m = 0, n = 0, i, ans;
for(i = 0; i < 7; i++) {
if(oper1 == op[i]) {
m = i;
}
if(oper2 == op[i]) {
n = i;
}
}
ans = cmp[m][n];
switch (ans) {
case 2:
return (char)('<');
case 1:
return (char)('>');
case 3:
return (char)('=');
default:
return 0;
}
}
- (CGFloat) countNum1:(CGFloat)num1 Num2:(CGFloat)num2 AndOper:(char)oper {
CGFloat val = 0;
switch (oper) {
case '+':
val = num1 + num2;
break;
case '-':
val = num1 - num2;
break;
case '*':
val = num1 * num2;
break;;
case '/':
val = num1 / num2;
break;
default:
break;
}
return val;
}
- (void) Calculat:(NSString *)calculationString {
[_Oper initStack];
[_Num initStack];
char* calculation = (char*)[calculationString UTF8String];
NSInteger length = calculationString.length;
char ch;
CGFloat x1, x2, val;
char oper;
int BracFlage = 0;
int flage = 0;
[_Oper Push:'='];
for (int i = 0; i < length; i++) {
ch = calculation[i];
if (![self inCalculator:ch]) {
val = 0;
while (![self inCalculator:ch] && i < length) {
val = val * 10 + (ch - '0');
ch = calculation[++i];
if (ch == '.') {
ch = calculation[++i];
int j = 1;
while (![self inCalculator:ch] && i < length) {
CGFloat f = (CGFloat)(ch - '0');
val = val + f / (10 * j);
j++;
ch = calculation[++i];
}
}
}
i--;
if (flage== 0) {
[_Num Push:val];
} else {
[_Num Push:-val];
flage = 0;
}
} else {
if (BracFlage == 0 || (ch != '-' && ch != '+')) {
switch([self CompareOper1:[_Oper GetTop] AndOper2:ch]) {
case '>':
[_Oper Push:ch];
break;
case '=':
[_Oper Pop];
break;
case '<':
oper = [_Oper Pop];
x2 = [_Num Pop];
x1 = [_Num Pop];
if (oper == '/' && x2 == 0) {
[[NSNotificationCenter defaultCenter] postNotificationName:@"error" object:nil];
return;
}
val = [self countNum1:x1 Num2:x2 AndOper:oper];
[_Num Push:val];
i--;
break;
default:
break;
}
}
if (BracFlage == 1 && ch == '-') {
flage = 1;
}
if (BracFlage == 1 && ch == ')') {
[[NSNotificationCenter defaultCenter] postNotificationName:@"error" object:nil];
return;
}
}
BracFlage = 0;
if (ch == '(') {
BracFlage = 1;
}
}
[self CGFloatToNSString:[_Num Pop]];
}
- (void) CGFloatToNSString:(CGFloat)answer {
NSMutableString* answerString = [NSMutableString stringWithFormat:@"%lf", answer];
if (![answerString isEqualToString:@"0"]) {
for (NSInteger i = answerString.length - 1; i >= 0; i--) {
NSString* s = [answerString substringWithRange:NSMakeRange(i, 1)];
if ([s isEqualToString:@"0"]) {
[answerString deleteCharactersInRange:NSMakeRange(i, 1)];
} else if ([s isEqualToString:@"."]) {
[answerString deleteCharactersInRange:NSMakeRange(i, 1)];
break;
} else {
break;;
}
}
}
NSDictionary* answerDict = [NSDictionary dictionaryWithObject:answerString forKey:@"Value"];
[[NSNotificationCenter defaultCenter] postNotificationName:@"answer" object:nil userInfo:answerDict];
}
@end
注：我使用两个flag分辨正负号和加减号。我们需要将加减号当作正负号处理的情况只有一种，就是在左括号后紧跟的加减号。我们一个flag检测左括号，一个flag检测加减号。如果我们在检测到左括号后紧跟着检测到加减号，就见此次加减号当作正负号处理。