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从NSInteger到NSNumber的隐含转换被禁止

问

I've written this piece of code:我写了这段代码：

    for (int i = 1; i < 1000; i++) {
          for (int j = 1; j < 1000; j++) {
              int k = i * j;                //This is the line were the error messages appears
              NSString *number = [NSString stringWithFormat:@"%d", k];
              NSNumber *length = number.length;
              NSNumber *half = (length / 2);  

What I want it to do, is to take the int k, convert it into a NSString named number, store the length of the string number in the NSNumber length, and half of that value in the NSNumber half.

我想要它做的是，获取int k，将其转换到NSString number，NSNumber length中存储number字符串的长度，并在NSNumber half 中存储该length值的一半。

但是，当尝试将int转换k为NSString时，number我收到错误消息：

However, when trying to convert the int k to the NSString number I get the error message:

"Implicit conversion of 'NSInteger' (aka 'unsigned int') to 'NSNumber *' is disallowed with arc"从NSInteger到NSNumber的隐含转换被禁止

Could someone help me figure out why?

 

答

number.length returns integer not NSNumber.number.length返回整数而不是NSNumber。

Correct it to :纠正它：

NSInteger length = number.length;
NSInteger half = (length / 2);  

If you really want to use NSNumber do like this: (Here I am boxing the integer to NSNumber object)如果你真的想使用NSNumber这样做:(这里我将整数装箱到NSNumber对象）

NSNumber *length = @(number.length); //same as [NSNumber numberWithInt:number.length]
NSNumber *half = @(number.length / 2);