Xcode iAction float，根据输入具有相等的不同数字

我对objective-c还不熟悉，只是在任何地方都找不到这个问题的答案。我正在运行一个iAction进行计算，但我需要一个标签的输入来实际等于等式中的其他内容

例如：

-(IBAction)calculate; {
  float a = 1.05 if ([label1.text] == 1in);
        a = 2.07 if ([label1.text] == 2in);
        a = 3.07 if ([label1.text] == 3in);
  float b = a*([textField1.text floatValue]);
        label2.text = [[NSString alloc] initWithFormat:@"%2.f", b];
  }

我知道我甚至还没做好，但我希望你能知道我在找什么

谢谢大家!

- (void)calculate {
  float a;
  if ([self.inputField.text isEqualToString:@"1in"])      a = 1.05f;
  else if ([self.inputField.text isEqualToString:@"2in"]) a = 2.07f;
  else if ([self.inputField.text isEqualToString:@"3in"]) a = 3.07f;
  else a = 0.0f;

  if (a) {
    float b = a * ([self.inputField.text floatValue]);
    self.inputField.text = [[NSString alloc] initWithFormat:@"%.2f", b];
  }
  else self.inputField.text = @"Invalid";
}

- (void)viewDidLoad
{
  //...

  self.inputField = [[UITextField alloc] initWithFrame:CGRectMake(10.0f, 20.0f, 300.0f, 30.0f)];
  [self.inputField setBackgroundColor:[UIColor grayColor]];
  [self.view addSubview:self.inputField];

  UIButton * doneButton = [[UIButton alloc] initWithFrame:CGRectMake(10.0f, 55.0f, 300.0f, 30.0f)];
  [doneButton setBackgroundColor:[UIColor blackColor]];
  [doneButton setTitle:@"Done" forState:UIControlStateNormal];
  [doneButton addTarget:self action:@selector(calculate) forControlEvents:UIControlEventTouchUpInside];
  [self.view addSubview:doneButton];
  [doneButton release];
}

注意：我将输出格式%2.f替换为%.2f，因为我想您可能需要此格式。例如：

Input > 1in
Output< 1.05

Input > 2in
Output< 4.14

Input > 3in
Output< 9.21

---

我不明白你想做什么，你的代码示例毫无意义，语法也不正确。你能再解释一下吗？谢谢！七月！很好用！