我正在编写一个旨在模拟珊瑚生长的程序，我希望珊瑚成为某种二叉树。分支相当于节点。当我运行程序时，我遇到了“分段错误”错误，经过测试和做一些研究后我认为这是因为Coral类的析构函数试图删除一个NULL对象。但是我不知道如何解决它，因为我不完全理解析构函数是如何工作的，而且我对类的概念一点也不熟悉。
我给你声明了CoralBranch和Coral类的头文件，实现类的.cpp和main.cpp。
提前谢谢大家。
使用最小，完整且可验证的示例来重现我的问题，我没有遇到任何问题。我认为我的程序中还有其他错误，这些错误会导致应该没有问题的方法的分段错误。
coral2.h
#ifndef __CORAL2_H_INCLUDED__
#define __CORAL2_H_INCLUDED__
class CoralBranch{
public:
CoralBranch(); // class constructor 1
CoralBranch(double xpos, double zpos, double th); // class constructor 2
~CoralBranch();
CoralBranch *left; // pointer to left child
CoralBranch *right; // pointer to right child
double x; // x-position of the beggining of the branch
double z; // z-position of the beggining of the branch
double theta; // branch's direction: angle between the branch and z-axis
double length; // branch's length
int state; // state==1: branch is able to grow, state==0: branch can't grow
};
class Coral{
public:
Coral(); // class constructor 1
Coral(double bl, double gr, double ir, double dt); // class constructor 2
~Coral(); // class destructor
// adds theta-oriented left son to coral-branch *leaf
void add_left(CoralBranch *leaf, double theta);
// adds theta-oriented right son to coral-branch *leaf
void add_right(CoralBranch *leaf, double theta);
// destroys coral-branch *branch and its decendents
void destroy_coral(CoralBranch *branch);
// tests if the growing branch influence zone penetrates testbranch influence zone
void distance_test(Coral crl, CoralBranch *growingbranch, CoralBranch *testbranch);
// tests if the growing branch is big enough to have children and adds them
void branching_test(Coral crl, CoralBranch *growingbranch, double thetaleft, double thetaright);
// applies grow mechanism to growing branch
void branch_grow(Coral crl, CoralBranch *growingbranch);
// simulates the growing process for the entire colony after one time step by
// applying "branch_grow" to the whole colony
void coral_grow(Coral crl, CoralBranch *growingbranch);
//private:
CoralBranch *trunk;
double branching_length;
double growth_rate;
double influence_radius;
double Deltat;
};
#endif
coral2.cpp（仅限构造函数和析构函数）
CoralBranch::CoralBranch():left(NULL),right(NULL),x(0.0),z(0.0),theta(0.0),length(1.0),state(1)
{
// there isn't any methods in this class
}
CoralBranch::CoralBranch(double xpos, double zpos, double th):left(NULL),right(NULL),x(xpos),z(zpos),theta(th),length(1.0),state(1)
{
}
CoralBranch::~CoralBranch(){
delete left;
delete right;
}
Coral::Coral(){
trunk=new CoralBranch();
branching_length=1.0;
growth_rate=1.0;
influence_radius=1.0;
Deltat=1.0;
}
Coral::Coral(double bl, double gr, double ir, double dt){
trunk=new CoralBranch();
//trunk=NULL;
branching_length=bl;
growth_rate=gr;
influence_radius=ir;
Deltat=dt;
}
Coral::~Coral(){ // coral destruction
destroy_coral(trunk);
}
void Coral::destroy_coral(CoralBranch *branch){ // destroys branch *branch and its decendents
if(branch == NULL) return;
destroy_coral(branch->left);
destroy_coral(branch->right);
delete branch;
/*if(branch!=NULL){
destroy_coral(branch->left); // destruction advance
destroy_coral(branch->right);
delete branch; // currently considered branch is deleted if it exists
}*/
}
的main.cpp
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include "coral2.h"
#include <math.h>
using namespace std;
int main(){
/* Variable declaration, these variables need to be initialized in order to
construct the coral with the characteristics we desire */
double branchinglength, growthrate, influenceradius, deltat;
/* Declaration and initialization of the total simulation time */
double TotalTime=2;
/* Declaration and initialization of counters */
int i=0;
int j=0;
printf("%d\n",j);
/* Initialization of Coral class parameters*/
branchinglength=0.2;
growthrate=1.0;
influenceradius=0.1;
deltat=1.0;
/* Creation of the coral object*/
static Coral GrowingCoral(branchinglength, growthrate, influenceradius, deltat);
/* Starting growth process */
for(i=0; i<TotalTime; i=i+deltat){
j++;
printf("%d\n",j);
GrowingCoral.coral_grow(GrowingCoral, GrowingCoral.trunk);
}
printf("%f\n",GrowingCoral.branching_length);
return 0;
}
答案 0 :(得分：1)
您要删除left和right分支两次。
考虑CoralBranch的工作原理：拥有 left分支和right分支。由于它拥有分支，因此它可以并且应该在析构函数delete中~CoralBranch。它确实如此！好。
您的班级Coral 仅拥有一个对象，trunk。但看看Coral::destroy_coral做了什么！允许删除类Coral 不拥有的分支对象！它应该销毁的唯一CoralBranch就是它所拥有的trunk destroy_coral。那个人将通过析构函数删除自己的子分支，并递归地删除它们自己的子分支。因此，您所要做的就是从destroy_coral中删除递归{{1}}调用。