C：如何舍入全局变量？

I have the code

我有代码

#include <stdio.h>
#include <math.h>

double x = round(3.2/2.0);

int main()
{
    printf("%f", x);
}

When I try to compile, I get the error initializer element is not a compile-time constant. Without round, it compiles without a hitch.

当我尝试编译时,我得到的错误初始化元素不是编译时常量。没有圆形,它编译顺利。

I want to round x while having it as a global variable. Is this possible?

我希望将x作为全局变量进行舍入。这可能吗?

2 个解决方案

#1

In C language objects with static storage duration can only be initialized with integral constant expressions. You are not allowed to call any functions in integral constant expressions.

在C语言中,具有静态存储持续时间的对象只能使用整数常量表达式进行初始化。不允许在整数常量表达式中调用任何函数。

You will have to find a way to generate your value through an integral constant expression. Something like this might work

您必须找到一种通过整数常量表达式生成值的方法。这样的事可能有用

double x = (int) (3.2 / 2.0 + 0.5);

#2

You can't call a function in the global scope, try

您无法在全局范围内调用函数,请尝试

#include <math.h>

double x;
int main(void) 
 {
    x = round(3.2 / 2.0);
    return 0;
 }

#1