ATOF和非空终止字符数组

问题描述

 使用命名空间std;
INT主（INT ARGC，CHAR *的argv []）{
    炭C [] = {'0'，'5''。'};
    //字符C [] =0.5;
    浮动F = ATOF（C）;
    COUT＆LT;＆LT; F * 10;
    如果（C [3]！='\\ 0'）
    {
        COUT＆LT;＆LT; 是;
    }
}
 

OUTPUT： 5YES

是否ATOF与非空终止字符数组太多的工作？如果是这样，它是如何知道在哪里停下？

解决方案

No, it doesn't. std::atof requires a null-terminated string in input. Failing to satisfy this precondition is Undefined Behavior.

Undefined Behavior means that anything could happen, including the program seeming to work fine. What is happening here is that by chance you have a byte in memory right after the last element of your array which cannot be interpreted as part of the representation of a floating-point number, which is why your implementation of std::atof stops. But that's something that cannot be relied upon.

You should fix your program this way:

char c[] = {'0', '.', '5', '\0'};
//                         ^^^^

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