打印字符串的反转 [英] print reverse of a string

问题描述

我正在编写一个程序，它在文本字段中打印字符串的反转，从另一个文本字段中获取输入文本。当我在一个文本字段中输入文本后按Enter键时，结果（反向）应显示在另一个文本字段中。

I am writing a program which prints the reverse of a string in a textfield, taking input text from the other textfield. When I press enter after entering text into one textfield the result(reverse) should be dispalyed in the other text field.

我试过这样的，但结果很奇怪。

I have tried like this, but am getting weird results.

.h文件：

#import <UIKit/UIKit.h>


@interface reverseVC : UIViewController {

    UITextField *textEntered;
    UITextField *textDisplay;

}
@property (nonatomic,retain) IBOutlet UITextField *textDisplay;
@property (nonatomic,retain) IBOutlet UITextField *textEntered;

- (NSMutableArray*) stringReverse;
- (IBAction) enter;

@end

.m文件

- (NSMutableArray *) stringReverse
{

    NSString *value = textEntered.text;
    NSArray *tempArray = [[[NSArray alloc] initWithObjects:value,nil] autorelease];

    NSMutableArray *arr = [[[NSMutableArray alloc] init] autorelease];


    for (int i=[tempArray count]-1; i>=0; i--)
    {
        [arr addObject:[tempArray objectAtIndex:i]];
        NSLog(@"the object is:%c",arr);
    }

    return arr;
}
-(IBAction)enter
{
   textDisplay.text = [NSString stringWithFormat:@"%c",[self stringReverse]];
}

在数组初始化中放置nil和autorelease之前，早先收到SIG_ABT和EXE_BAD_ACCESS等警告。现在警告已经解决但结果出乎意料。

Earlier got warnings like SIG_ABT and EXE_BAD_ACCESS before placing nil and autorelease in array initialisations. Now the warnings are solved but results undesiredly.

我哪里出错？

推荐答案

使用此

NSString *str=textEntered.text;//
    NSMutableArray *temp=[[NSMutableArray alloc] init];
    for(int i=0;i<[str length];i++)
    {
        [temp addObject:[NSString stringWithFormat:@"%c",[str characterAtIndex:i]]];
    }
    temp = [NSMutableArray arrayWithArray:[[temp reverseObjectEnumerator] allObjects]];
    NSString *reverseString=@"";
    for(int i=0;i<[temp count];i++)
    {
        reverseString=[NSString stringWithFormat:@"%@%@",reverseString,[temp objectAtIndex:i]];
    }
    NSLog(@"%@",reverseString);

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