小编Asa*_*sap的帖子

#include<iostream>  
using namespace std;  
class base {  
public:     
    base() {
        cout<<"Constructing base \n";
    }  
    virtual ~base() {
        cout<<"Destructing base \n";
    } 
};  
class derived: public base { 
public:    
    derived() {
        cout<<"Constructing derived \n";
    }    
    ~derived() {
        cout<<"Destructing derived \n";
    }
};   
int main(void) {
    derived d();     
    return 0; 
} 

为什么在这个程序中它没有调用构造函数？

谁能解释一下？
.......

#include<stdio.h>
#include<string.h>

struct s {
    char ch[20];
    float a;
};

int main()
{
    struct s p[10];
    int i;
    for(i=0;i<10;i++)
    {
        scanf("%s%f",p[i].ch,p[i].a);
    }
}

这段代码有什么问题？

它给出了运行时错误.

有什么问题？