小编dog*_*719的帖子

来自Java和C#世界,我总是喜欢使用

someclass a = someclass();

代替

someclass a();

在C++中初始化一个类变量.但是,我的编译器有时会抱怨

Error C2280: Attempting to reference a deleted function

它们之间有什么区别吗？哪一个更好？

在C中,有符号整数和无符号整数在内存中的存储方式不同.当类型在运行时清除时,C还隐式转换有符号整数和无符号整数.但是,当我尝试以下代码段时,

#include <stdio.h>

int main() {    
    unsigned int a = 5;
    signed int b = a;
    signed int c = *(unsigned int*)&a;
    signed int d = *(signed int*)&a;

    printf("%u\n", a);
    printf("%i\n", b);
    printf("%i\n", c);
    printf("%i\n", d);

    return 0;
}

预期产量:

5
5                   //Implicit conversion occurs
5                   //Implicit conversion occurs, because it knows that *(unsigned int*)&a is an unsigned int
[some crazy number] //a is casted directly to signed int without conversion

然而,实际上,它输出

5
5
5
5

为什么？