ios - 字符串的 NSArray

Question

我正在尝试创建一个 NSMutableArray 字符。

lowerCaseLetters = [NSMutableArray new];
for (char crt = 'a'; crt <= 'z'; crt ++) {
    NSString *chrStr = [NSString stringWithCString:&crt encoding:NSUTF8StringEncoding];
    [lowerCaseLetters addObject:chrStr];
}
NSLog(@"%@",lowerCaseLetters);

结果:

  "a@Ip",
    "b@Ip",
    "c@Ip",
    "d@Ip",
    "e@Ip",
    "f@Ip",
    "g@Ip",
    "h@Ip",
    "i@Ip",
    "j@Ip",
    "k@Ip",
    "l@Ip",
    "m@Ip",
    "n@Ip",
    "o@Ip",
    "p@Ip",
    "q@Ip",
    "r@Ip",
    "s@Ip",
    "t@Ip",
    "u@Ip",
    "v@Ip",
    "w@Ip",
    "x@Ip",
    "y@Ip",
    "z@Ip"
)

为什么我会得到这个？有一个更好的方法吗？PS:有时这会因“insertObject:atIndex:”而崩溃无法插入 nil 对象....为什么？

Answer 1

这是未定义的行为:

NSString *chrStr = [NSString stringWithCString:&crt encoding:NSUTF8StringEncoding];

问题是 &crt 不是 C 字符串，因为 C 字符串必须以 null 结尾。您可以这样修复它:

char buf[2];
buf[0] = crt;
buf[1] = '\0';
NSString *chrStr = [NSString stringWithCString:buf encoding:NSUTF8StringEncoding];

您还可以使用 stringWithFormat: 作为更简单的方法，如下所示:

NSString *chrStr = [NSString stringWithFormat:@"%c", crt];