Question

请参阅下面我的c ++代码片段。因为foo.h是在int main（int argc，char * argv []）之前执行的，所以数组RedApple将初始化为0并导致错误。处理这个问题的最佳方法是什么？有没有办法在foo.h中保留类声明，但是从用户输入中在foo.cpp中初始化它？谢谢！

在foo.h中

#include <vector>
extern int num;
class apple
{
std::vector<long> RedApple;
public:
    apple(): RedApple(num)
}

在foo.cpp

#include    "foo.h"
int num;
int main(int argc, char *argv[])
{
sscanf_s(argv[1],"%d",&num);
}

Answer 1

在foo.h中

#include <vector>

class apple
{
std::vector<long> RedApple;
public:
    apple(){}
    apple(int num): RedApple(num){}
}

在foo.cpp

#include    "foo.h"

int main(int argc, char *argv[])
{
    int num;
    sscanf_s(argv[1],"%d",&num);

    apple foo = num > 0 ? apple(num) : apple();
}

修改在回复Klaus投诉时，我想我会添加初始化的解释，我正在评论第apple foo = num > 0 ? apple(num) : apple();行，所以我会在每个单词上对其进行垂直评论：

apple // This is the type of variable in the same way int is the type of int num; foo // The name of the apple object that I am creating = // Normally this will trigger the assignment operator (but in a declaration line the compiler will optimize it out) num > 0 ? // The condition to a ternary operator if true the statement before the : is executed if false the one after is executed apple(num) // If num is greater than 0 use the non-default constructor : apple(); // If num is less than or equal to 0 use the default number cause we can't initialize arrays negatively

在头文件中声明一个类，并从用户输入初始化该类的数组

1 个答案: