在运行时调试 [英] Debugging at runtime

问题描述

我是一个完全的初学者，编写了我的第二个程序，最后

得到它编译，我有一个错误我可以'跟踪发生在

运行时间 - 基本上无论我做什么都说分段错误。

我想知道是否有任何方法我可以得到更多

详细描述错误，以便我可以考虑对它进行排序

out。


有人向我提到g ++选项-DRANGE_CHECKING将

检查我是否正在访问未初始化的数组或某些东西在编译

时间，但这没有帮助，在此先感谢，我真的在我的智慧

结束！

Hi,
I''m a complete beginner, having written my second program and finally
got it to compile, I''ve got an error I can''t track down occurring at
runtime - basically whatever I do it says Segmentation Fault.
I was wondering if there was any way I could get a slightly more
verbose description of the error so that I could think about sorting it
out.

Someone mentioned to me that the g++ option -DRANGE_CHECKING would
check if i was accessing uninitialised arrays or something at compile
time, but that hasn''t helped, Thanks in advance, I''m really at my wits
end!

推荐答案

Cleverbum写道：

Cleverbum wrote:

我是一个完全的初学者，编写了我的第二个程序，最后得到了编译，我有一个错误，我无法追踪发生在
运行时 - 基本上无论我做什么都说分段错误。

I''m a complete beginner, having written my second program and finally
got it to compile, I''ve got an error I can''t track down occurring at
runtime - basically whatever I do it says Segmentation Fault.

这个新闻组只有资格讨论C ++源码;不是所有的各种

实现和工具，包括调试器。


你可以在这里发布一些来源 - 大多数seg故障很容易发现 - 或者你/>
可以将关于调试的问题发布到g ++新闻组。


-

Phlip
http://c2.com/cgi/wiki?ZeekLand < - 不是博客!! ！

This newsgroup is only qualified to discuss C++ source; not all its various
implementations and tools, including debuggers.

You could post some source here - most seg faults are easy to spot - or you
could post your question about debugging to a g++ newsgroup.

--
Phlip
http://c2.com/cgi/wiki?ZeekLand <-- NOT a blog!!!

似乎编译器新闻组只发布到每两天

左右，所以我不妨在这里发布代码，通过它几次我自己并没有找到任何不幸的事情：


/ *模型颗粒在三维空间内沉降。

还包括粒子间重力* /

#include< iostream>

#include< math.h>

#include< fstream>

#include< sstream>

#include< string >

#include< time.h>

using namespace std;


const int n = 1; //粒子数

const double G = 6.6742e-11; //万能引力常数

const double gravity = 9.81; //由于重力引起的自由落体加速

const int max_time = 100;

const int timeStep = 1;


struct vec_3d {

double x，y，z;

};


class particle {

//所有向量存储为数组[0] = x dir [1] = y dir [2] = z dir

私有：

double * pos;

double * vel;

double * frc;

双倍质量;

bool hard;

double rad;

public：

particle（）{

srand（time（0））;

int randint = 0;

for（int i = 0; i< 3; i ++）{

randint = rand（）％1000;

pos [i] = randint / 1000.0;

vel [i] = 0.0;

frc [i] = 0.0;

}

质量= 1.0;

rad = 1.0;

hard = true;

}


// void move（double *）; //作为数组提供的速度

// void move（vec_3d）; //作为矢量结构提供的速度

void move（）; //使用粒子对象中保存的速度


// void acceleration（double *）; //作为数组提供的力

// void accelerated（vec_3d）; //作为向量提供的力

void accelerate（）; //使用存储在粒子对象中的力


string toString（）{

ostringstream os;

os<< pos [0]<< ''\t''

<< pos [1]<< ''\t''

<< pos [2]<< ''\t''

<< vel [0]<< ''\t''

<< vel [1]<< ''\t''

<< vel [2]<< ''\t'';

返回os.str（）;

};


friend void calculate_forces（particle ，粒子）;

朋友无效single_particle_forces（粒子）;

};


main（）{

particle * myParticles = new particle [n];

for（int simulation_time = 0; simulation_time< max_time; simulation_time

+ = timeStep）{

for（int i = 0; i< n; i ++）{

if（n> 1）{

for（int j = i + 1; j< n; j ++）{

calculate_forces（myParticles [i]，myParticles [j]）;

}

}

single_particle_forces（myParticles [i]）;

myParticles [i] .accelerate（）;

myParticles [i] .move（）;

cout<< i<< myParticles [i] .toString（）;

}

}


}


void particle :: move（）{

for（int j = 0; j< 3; j ++）{

pos [j] + = vel [j] * timeStep;

}

}


void particle :: accele（）{

for （int j = 0; j< 3; j ++）{

vel [j] + = frc [j] * timeStep;

}

}


void calculate_forces（粒子x，粒子y）{

for（int i = 0; i< 3; i ++）{

//身体之间的引力吸引力

int mySign; //用于确定力的方向

if（y.pos [i]> x.pos [i]）{mySign = -1;} else {mySign = 1;}

x.frc [i] = mySign * G * x.mass * y.mass /（（y.pos [i] - x.pos [i]）*（

y.pos [i] - x.pos [i]））;

y.frc [i] = -1 * mySign * G * x.mass * y.mass /（（y。 pos [i] -

x.pos [i]）*（y.pos [i] - x.pos [i]））;

}

}

void single_particle_forces（粒子x）{

//重力在z轴上呈负值

x.frc [2 ] - = x.mass * gravity;

}

seems the compiler newsgroups are only posted to every couple of days
or so, so I may as well post the code here, been through it a few times
myself and have had no luck in spotting anything untoward:

/* models particle(s) settling under gravity in three dimensions.
also includes inter-particle gravity */

#include <iostream>
#include <math.h>
#include <fstream>
#include <sstream>
#include <string>
#include <time.h>
using namespace std;

const int n = 1; // number of particles
const double G = 6.6742e-11; // universal gravitational constant
const double gravity = 9.81; // freefall acceleration due to gravity
const int max_time =100;
const int timeStep = 1;

struct vec_3d{
double x, y, z;
};

class particle{
// all vectors stored as arrays [0]=x dir [1]=y dir [2]=z dir
private:
double* pos;
double* vel;
double* frc;
double mass;
bool hard;
double rad;
public:
particle(){
srand(time(0));
int randint = 0;
for(int i=0;i<3;i++){
randint = rand()%1000;
pos[i] = randint / 1000.0;
vel[i]=0.0;
frc[i]=0.0;
}
mass=1.0;
rad=1.0;
hard=true;
}

//void move(double*); // speeds supplied as array
//void move(vec_3d); // speeds supplied as vector structure
void move(); // uses speeds saved within particle object

//void accelerate(double*); // forces supplied as array
//void accelerate(vec_3d); // forces supplied as vector
void accelerate(); // uses forces stored inside particle object

string toString(){
ostringstream os;
os << pos[0] << ''\t''
<< pos[1] << ''\t''
<< pos[2] << ''\t''
<< vel[0] << ''\t''
<< vel[1] << ''\t''
<< vel[2] << ''\t'';
return os.str();
} ;

friend void calculate_forces(particle, particle);
friend void single_particle_forces(particle);
};

main(){
particle* myParticles = new particle[n];
for(int simulation_time=0;simulation_time<max_time; simulation_time
+= timeStep){
for(int i=0; i<n; i++){
if(n>1){
for(int j=i+1; j<n; j++){
calculate_forces(myParticles[i], myParticles[j]);
}
}
single_particle_forces(myParticles[i]);
myParticles[i].accelerate();
myParticles[i].move();
cout << i << myParticles[i].toString();
}
}

}

void particle::move(){
for(int j=0;j<3;j++){
pos[j] += vel[j] * timeStep;
}
}

void particle::accelerate(){
for(int j=0;j<3;j++){
vel[j] += frc[j] * timeStep;
}
}

void calculate_forces(particle x, particle y){
for(int i=0;i<3;i++){
//Gravitational attraction between the bodies
int mySign; //used to determine direction of force
if(y.pos[i]>x.pos[i]){mySign = -1;} else {mySign = 1;}
x.frc[i] = mySign * G * x.mass * y.mass / (( y.pos[i] - x.pos[i])*(
y.pos[i] - x.pos[i]));
y.frc[i] = -1 * mySign * G * x.mass * y.mass / (( y.pos[i] -
x.pos[i])*( y.pos[i] - x.pos[i]));
}
}
void single_particle_forces(particle x){
//gravity acts negative on z axis
x.frc[2] -= x.mass * gravity;
}

Cl ******* @ hotmail.com 写道：

似乎编译新闻组只发布到每两天
或许，所以我也可以在这里发布代码，自己经历了几次，并且没有发现任何不幸的事情：

[...]
类粒子{
//所有向量存储为数组[0] = x dir [1] = y dir [2] = z dir
pri vate：
double * pos;
double * vel;
double * frc;
double mass;
bool hard;
double rad;
public：
particle（）{
srand（time（0））;
int randint = 0;
for（int i = 0; i< 3; i ++）{
randint = rand（）％1000;
pos [i] = randint / 1000.0;


''pos''指针从未被初始化。你正在取消引用

一个未初始化（无效）的指针。


vel [i] = 0.0;
frc [i] = 0.0;
}
质量= 1.0;
rad = 1.0;
hard = true;
}

[...] };

main（）{


int main（）{

[...]

seems the compiler newsgroups are only posted to every couple of days
or so, so I may as well post the code here, been through it a few
times myself and have had no luck in spotting anything untoward:

[...]

class particle{
// all vectors stored as arrays [0]=x dir [1]=y dir [2]=z dir
private:
double* pos;
double* vel;
double* frc;
double mass;
bool hard;
double rad;
public:
particle(){
srand(time(0));
int randint = 0;
for(int i=0;i<3;i++){
randint = rand()%1000;
pos[i] = randint / 1000.0;
''pos'' pointer has never been initialised. You''re dereferencing
an uninitialised (invalid) pointer.

vel[i]=0.0;
frc[i]=0.0;
}
mass=1.0;
rad=1.0;
hard=true;
}

[...]
};

main(){
int main(){
[...]

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