C++ program produces an exception to? - c++

why an error occurs An exception was thrown at address 0x003329B0 in ConsoleApplication1.exe: 0xC0000005: access violation occurred while writing to address 0xCCCCCCCC
#include <iostream>
#include <time.h>
#include <random>
//------------------
using namespace::std;
//------------------
void input(int* size)
{
cout << "Input pleas size your diapason of array";
cout << endl;
cin >> (*size);
};
void randomizer(int** array, int& size)
{
srand(time(NULL));
int result = rand() % size;
result += 1;
for (int i = 1; i <= result; i++)
{
(*array[i]) = rand() % 100;
if (i % 2)
{
(*array[i]) *= -1;
}
};
(*array)[0] = result;
};
//------------------------------------------------------
int ittMOD(int** array)
{
int result = 0;
int itt = (*array)[1];
for (int i(0); i < (*arrey[0]); i++)
{
if (itt < 0)
{
itt *= -1;
};
if (itt < (*array[i]))
{
itt = (*array[i]);
result = i;
};
return result;
};
};
int main()
{
setlocale(LC_ALL, "RUSSIAN");
//---------------------------
int* array = new int;
int size = 0;
//---------------------------
input(&size);
randomizer(&array, size);
cout << ittMOD(`&array);
cout << endl;
//cout << summELEMENTS(arrey);
delete array;
array = NULL;
return 0;
};

Related

'this' cannot be used in a constant expression error

The error is on line 76 int res[mSize]; the problem is on mSize. It seems like a simple fix but I can't figure it out. If someone can figure it out or point me in the right direction that would be greatly appreciated.
Also, the deconstructor ~MyContainer(), I am not sure if I am using it right or if there is a correct place to put it.
Here is my code:
#include <iostream>
using namespace std;
class MyContainer
{
private:
int* mHead; // head of the member array
int mSize; // size of the member array
public:
MyContainer();
MyContainer(int*, int);
//~MyContainer();
void Add(int);
void Delete(int);
int GetSize();
void DisplayAll();
int FindMissing();
~MyContainer() {}
};
MyContainer::MyContainer()
{
mHead = NULL;
mSize = 0;
}
MyContainer::MyContainer(int* a, int b)
{
mHead = a;
mSize = b;
}
void MyContainer::Add(int a)
{
*(mHead + mSize) = a;
mSize++;
}
void MyContainer::Delete(int a)
{
int index;
for (int i = 0; i < mSize; i++)
{
if (*(mHead + i) == a)
{
index = i;
break;
}
}
for (int i = index; i < mSize; i++)
{
*(mHead + i) = *(mHead + i + 1);
}
mSize--;
}
int MyContainer::GetSize()
{
return mSize;
}
void MyContainer::DisplayAll()
{
cout << "\n";
for (int i = 0; i < mSize; i++)
{
cout << *(mHead + i) << " ";
}
}
int MyContainer::FindMissing()
{
int res[mSize];
int temp;
int flag = 0;
for (int i = 1; i <= mSize; i++)
{
flag = 0;
for (int j = 0; j < mSize; j++)
{
if (*(mHead + j) == i)
{
flag = 1;
break;
}
}
if (flag == 0)
{
temp = i;
break;
}
}
return temp;
}
int main()
{
const int cSize = 5;
int lArray[cSize] = { 2, 3, 7, 6, 8 };
MyContainer lContainer(lArray, cSize);
lContainer.DisplayAll();
lContainer.Delete(7);
lContainer.DisplayAll();
cout << "Size now is: " << lContainer.GetSize() << endl; lContainer.Add(-1);
lContainer.Add(-10);
lContainer.Add(15);
lContainer.DisplayAll();
cout << "Size now is: " << lContainer.GetSize() << endl;
cout << "First missing positive is: " << lContainer.FindMissing() << endl;
system("PAUSE"); return 0;
}
int res[mSize];
The size of the array mSize must be known at compile time. You cannot use a variable here. An option may be to define a macro with an largish value that will not exceeded.
static const int kLargeSize =100;
int res[kLargeSize];
Edited in response to the comments - const and constexpr are a better option than a macro.
Or even better, you can use std::vector - https://en.cppreference.com/w/cpp/container/vector

c++ - Segmentation fault for class function of vector of custom class

I am using following code to run kmeans algorithm on Iris flower dataset- https://github.com/marcoscastro/kmeans/blob/master/kmeans.cpp
I have modified the above code to read input from files. Below is my code -
#include <iostream>
#include <vector>
#include <math.h>
#include <stdlib.h>
#include <time.h>
#include <algorithm>
#include <fstream>
using namespace std;
class Point
{
private:
int id_point, id_cluster;
vector<double> values;
int total_values;
string name;
public:
Point(int id_point, vector<double>& values, string name = "")
{
this->id_point = id_point;
total_values = values.size();
for(int i = 0; i < total_values; i++)
this->values.push_back(values[i]);
this->name = name;
this->id_cluster = -1;
}
int getID()
{
return id_point;
}
void setCluster(int id_cluster)
{
this->id_cluster = id_cluster;
}
int getCluster()
{
return id_cluster;
}
double getValue(int index)
{
return values[index];
}
int getTotalValues()
{
return total_values;
}
void addValue(double value)
{
values.push_back(value);
}
string getName()
{
return name;
}
};
class Cluster
{
private:
int id_cluster;
vector<double> central_values;
vector<Point> points;
public:
Cluster(int id_cluster, Point point)
{
this->id_cluster = id_cluster;
int total_values = point.getTotalValues();
for(int i = 0; i < total_values; i++)
central_values.push_back(point.getValue(i));
points.push_back(point);
}
void addPoint(Point point)
{
points.push_back(point);
}
bool removePoint(int id_point)
{
int total_points = points.size();
for(int i = 0; i < total_points; i++)
{
if(points[i].getID() == id_point)
{
points.erase(points.begin() + i);
return true;
}
}
return false;
}
double getCentralValue(int index)
{
return central_values[index];
}
void setCentralValue(int index, double value)
{
central_values[index] = value;
}
Point getPoint(int index)
{
return points[index];
}
int getTotalPoints()
{
return points.size();
}
int getID()
{
return id_cluster;
}
};
class KMeans
{
private:
int K; // number of clusters
int total_values, total_points, max_iterations;
vector<Cluster> clusters;
// return ID of nearest center (uses euclidean distance)
int getIDNearestCenter(Point point)
{
double sum = 0.0, min_dist;
int id_cluster_center = 0;
for(int i = 0; i < total_values; i++)
{
sum += pow(clusters[0].getCentralValue(i) -
point.getValue(i), 2.0);
}
min_dist = sqrt(sum);
for(int i = 1; i < K; i++)
{
double dist;
sum = 0.0;
for(int j = 0; j < total_values; j++)
{
sum += pow(clusters[i].getCentralValue(j) -
point.getValue(j), 2.0);
}
dist = sqrt(sum);
if(dist < min_dist)
{
min_dist = dist;
id_cluster_center = i;
}
}
return id_cluster_center;
}
public:
KMeans(int K, int total_points, int total_values, int max_iterations)
{
this->K = K;
this->total_points = total_points;
this->total_values = total_values;
this->max_iterations = max_iterations;
}
void run(vector<Point> & points)
{
if(K > total_points)
return;
vector<int> prohibited_indexes;
printf("Inside run \n");
// choose K distinct values for the centers of the clusters
printf(" K distinct cluster\n");
for(int i = 0; i < K; i++)
{
while(true)
{
int index_point = rand() % total_points;
if(find(prohibited_indexes.begin(), prohibited_indexes.end(),
index_point) == prohibited_indexes.end())
{
printf("i= %d\n",i);
prohibited_indexes.push_back(index_point);
points[index_point].setCluster(i);
Cluster cluster(i, points[index_point]);
clusters.push_back(cluster);
break;
}
}
}
int iter = 1;
printf(" Each point to nearest cluster\n");
while(true)
{
bool done = true;
// associates each point to the nearest center
for(int i = 0; i < total_points; i++)
{
int id_old_cluster = points[i].getCluster();
int id_nearest_center = getIDNearestCenter(points[i]);
if(id_old_cluster != id_nearest_center)
{
if(id_old_cluster != -1)
clusters[id_old_cluster].removePoint(points[i].getID());
points[i].setCluster(id_nearest_center);
clusters[id_nearest_center].addPoint(points[i]);
done = false;
}
}
// recalculating the center of each cluster
for(int i = 0; i < K; i++)
{
for(int j = 0; j < total_values; j++)
{
int total_points_cluster = clusters[i].getTotalPoints();
double sum = 0.0;
if(total_points_cluster > 0)
{
for(int p = 0; p < total_points_cluster; p++)
sum += clusters[i].getPoint(p).getValue(j);
clusters[i].setCentralValue(j, sum / total_points_cluster);
}
}
}
if(done == true || iter >= max_iterations)
{
cout << "Break in iteration " << iter << "\n\n";
break;
}
iter++;
}
// shows elements of clusters
for(int i = 0; i < K; i++)
{
int total_points_cluster = clusters[i].getTotalPoints();
cout << "Cluster " << clusters[i].getID() + 1 << endl;
for(int j = 0; j < total_points_cluster; j++)
{
cout << "Point " << clusters[i].getPoint(j).getID() + 1 << ": ";
for(int p = 0; p < total_values; p++)
cout << clusters[i].getPoint(j).getValue(p) << " ";
string point_name = clusters[i].getPoint(j).getName();
if(point_name != "")
cout << "- " << point_name;
cout << endl;
}
cout << "Cluster values: ";
for(int j = 0; j < total_values; j++)
cout << clusters[i].getCentralValue(j) << " ";
cout << "\n\n";
}
}
};
int main(int argc, char *argv[])
{
srand(time(NULL));
int total_points, total_values, K, max_iterations, has_name;
ifstream inFile("datafile.txt");
if (!inFile) {
cerr << "Unable to open file datafile.txt";
exit(1); // call system to stop
}
inFile >> total_points >> total_values >> K >> max_iterations >> has_name;
cout << "Details- \n";
vector<Point> points;
string point_name,str;
int i=0;
while(inFile.eof())
{
string temp;
vector<double> values;
for(int j = 0; j < total_values; j++)
{
double value;
inFile >> value;
values.push_back(value);
}
if(has_name)
{
inFile >> point_name;
Point p(i, values, point_name);
points.push_back(p);
i++;
}
else
{
inFile >> temp;
Point p(i, values);
points.push_back(p);
i++;
}
}
inFile.close();
KMeans kmeans(K, total_points, total_values, max_iterations);
kmeans.run(points);
return 0;
}
Output of code is -
Details-
15043100000Inside run
K distinct cluster i= 0
Segmentation fault
When I run it in gdb, the error shown is -
Program received signal SIGSEGV, Segmentation fault.
0x0000000000401db6 in Point::setCluster (this=0x540, id_cluster=0)
at kmeans.cpp:41
41 this->id_cluster = id_cluster;
I am stuck at this as I cannot find the cause for this segmentation fault.
My dataset file looks like -
150 4 3 10000 1
5.1,3.5,1.4,0.2,Iris-setosa
4.9,3.0,1.4,0.2,Iris-setosa
4.7,3.2,1.3,0.2,Iris-setosa
. . .
7.0,3.2,4.7,1.4,Iris-versicolor
6.4,3.2,4.5,1.5,Iris-versicolor
6.9,3.1,4.9,1.5,Iris-versicolor
5.5,2.3,4.0,1.3,Iris-versicolor
6.5,2.8,4.6,1.5,Iris-versicolor
. . .
in KMeans::run(vector<Point>&) you call points[index_point].setCluster(i); without any guarantee that index_point is within bounds.
index_point is determined by int index_point = rand() % total_points;, and total_points is retrieved from the input file "datafile.txt" which could be anything. It certainly does not have to match points.size(), but it should. Make sure it does, or just use points.size() instead.
A bit offtopic, but using rand() and only using modulo is almost always wrong. If you use C++11 or newer, please consider using std::uniform_int_distribution.
points[index_point].setCluster(i); could be accessing the vector out of bounds. The code you quoted actually always sets a number of total_points in the vector points before calling run, while your modified code just reads until end of file and has no guarantees that the number of total points passed to the constructor of KMeans matches the value of entries in points. Either fix your file I/O or fix the logic of bounds checking.

Inputting the amount you want displayed in the array

I am writing a program that displays integer arrays. I set the size of the array, but I am wondering how I can ask the user the index of the array that they want listed. Say the const SIZE = 10, and the user wants to see the first three in the array. I want to also write an exception that catches the error if the user input is over the size of the array. If you need to see some code, let me know. Any help is appreciated!
intergerarray.h
class IntArray
{
private:
int *aptr; // Pointer to the array
int arraySize; // Holds the array size
void subscriptError(); // Handles invalid subscripts
public:
class OutOfBoundException
{
public:
int index;
OutOfBoundException(){};
int getInde() { return index; }
};
IntArray(int); // Constructor
IntArray(const IntArray &); // Copy constructor
~IntArray(); // Destructor
int size() const // Returns the array size
{
return arraySize;
}
int &operator[](const int &); // Overloaded [] operator
};
IntergerArray.cpp
IntArray::IntArray(int s)
{
arraySize = s;
aptr = new int[s];
for (int count = 0; count < arraySize; count++)
*(aptr + count) = 0;
}
IntArray::IntArray(const IntArray &obj)
{
arraySize = obj.arraySize;
aptr = new int[arraySize];
for (int count = 0; count < arraySize; count++)
*(aptr + count) = *(obj.aptr + count);
}
IntArray::~IntArray()
{
if (arraySize > 0)
delete[] aptr;
}
void IntArray::subscriptError()
{
cout << "ERROR: Subscript out of range.\n";
exit(0);
}
int &IntArray::operator[](const int &sub)
{
if (sub < 0 || sub >= arraySize)
subscriptError();
return aptr[sub];
}
driver file.cpp
int main()
{
int SIZE = 10;
//int index;
//cout << "enter an index";
//cin >> index;
IntArray table(SIZE);
for (int x = 0; x < SIZE; x++)
table[x] = x;
for (int x = 0; x < SIZE; x++)
cout << table[x] << " ";
cout << endl;
//table[SIZE + 1] = 0;
return 0;
}
Isn't this what you are trying to do? why so much code for such a simple problem?
const int arraySize = 10;
int array[arraySize];
int elementToDis;
do
{
std::cout << "Number of array elements to display: ";
std::cin >> elementToDis;
} while (elementToDis > arraySize || elementToDis < 0); // this is your exeption
for (int ccc(0); ccc < elementToDis; ++ccc)
std::cout << "Index " << ccc << ": " << array[ccc] << '\n';
I think you want to display all elements lower than an index value entered by the user :
Let array[] be the array name of size=10,you can get an index value (say l) from the user and use that value inside a for loop for printing all elements in index lower than l
int array[size]
void disp_in(int l)
{
if(l>=size) // if l greater than or equal to size (as index start at 0)
throw l;
else
{
cout<<"Elements : ";
for(int i=0;i<=l;i++) //if we have say l=2 ,array values in indexes 0,1and 2 will be displayed
cout<<array[i];
}
}
int main ()
{
int l;
cout<<"Enter index : ";
cin>>l; //till this index value, the array value will be displayed
try
{
disp_in(l);
}
catch(int e)
{
cout<<"Index value greater than max index";
}
return 0;
}
You could try something like this:
#include <vector>
#include <iostream>
#include <algorithm>
#include <iterator>
void print_numbers( const std::vector<int>& array, int nNumbers, const char* pszSeparator )
{
if ( nNumbers > static_cast<int>(array.size()) )
{
throw std::exception();
}
std::copy( array.begin(), array.begin() + nNumbers, std::ostream_iterator<int>( std::cout, pszSeparator ) );
}
int main()
{
std::vector<int> array( 10 );
//Just for testing
{
int n = 0;
auto generator = [n]() mutable
{
return n++;
};
std::generate_n( array.begin(), array.size(), generator );
}
try
{
print_numbers(array, 11, "\n");
}
catch ( std::exception e )
{
std::cout << "Error message..." << std::endl;
}
return 0;
}

MSVC Debugger tells me that my vector has more positions than specified

I have declared the following:
const int NUMBER_OF_DIGITS = 16;
std::vector<int> digits(NUMBER_OF_DIGITS);
However when I open the MSVC debugger it shows the following:
This is how I added values to the vector:
for (int i = 0; i < NUMBER_OF_DIGITS; ++i) {
scanf("%d", &digits[i]);
}
Is this normal? Can I just ignore this? Or is this a problem?
Full code(the program is still not ready yet):
#include <iostream>
#include <vector>
#include "stdio.h"
const int NUMBER_OF_DIGITS = 16;
int checksum, tmp1, tmp2, tmp3, sum = 0;
std::vector<int> digits(NUMBER_OF_DIGITS);
std::vector<int> new_digits(NUMBER_OF_DIGITS);
int luhn_checksum(std::vector<int> cardnumber[NUMBER_OF_DIGITS]) {
//step 1: duouble every second number
for (int i = 1; i < NUMBER_OF_DIGITS; i += 2) {
new_digits[i] = digits[i] * 2;
if (new_digits[i] > 9) {
//if the product is larger than 9 we will add the two numbers together
//example: 9 * 2 = 18 so we will add 1 + 8 to get 9
tmp1 += new_digits[i] % 10;
new_digits[i] /= 10;
tmp1 = 0;
}
}
//step 2: sum all the values
for (int i = 0; i < NUMBER_OF_DIGITS; ++i) {
checksum += new_digits[i];
}
return checksum;
}
void get_card_numbers(void) {
for (int i = 0; i < NUMBER_OF_DIGITS; ++i) {
scanf("%d", &digits[i]);
}
}
void initialize(void) {
for (int i = 0; i < NUMBER_OF_DIGITS; ++i) {
digits.push_back(0);
new_digits.push_back(0);
}
}
int main() {
initialize();
get_card_numbers();
printf("checksum is: %d\n", luhn_checksum(&digits));
std::cout << digits.size() << std::endl;
int x; scanf("%d", &x);
return 0;
}
The constructor you're using for digits is setting the size by specifying the count. So after calling push_back you've just added another 16 to the vector. Use a different constructor that doesn't set the count.
int _tmain(int argc, _TCHAR* argv[])
{
const int NUMBER_OF_DIGITS = 16;
std::vector<int> digits(NUMBER_OF_DIGITS);
//std::vector<int> digits;
int digitsLen = digits.size();
// Here is 16
for (int i = 0; i < NUMBER_OF_DIGITS; ++i) {
digits.push_back(0);
}
int digitsLen2 = digits.size();
// Here is 32
return 0;
}
Cleaned up your code a bit:
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
static const size_t NUMBER_OF_DIGITS = 16;
class cards {
public:
cards();
void read();
int luhnChecksum() const;
private:
vector<int> digits;
};
cards::cards() : digits(NUMBER_OF_DIGITS, 0)
{
}
void cards::read() {
for_each(digits.begin(), digits.end(), [](int& i) { cin >> i; });
}
int cards::luhnChecksum() const {
vector<int> newdigits(digits.begin(), digits.end());
for (size_t i=1; i<NUMBER_OF_DIGITS; i += 2) {
newdigits[i] = digits[i] * 2;
if (newdigits[i] > 9) {
int tmp1 = newdigits[i] % 10;
newdigits[i] /= 10;
newdigits[i] += tmp1;
}
}
return accumulate(newdigits.begin(), newdigits.end(), 0);
}
int main() {
cards c;
c.read();
cout << "checksum = " << c.luhnChecksum() << endl;
return 0;
}

Program gives a weird runtime error

#include<iostream>
using namespace std;
class darray
{
private:
int n; // size of the array
int *a; // pointer to the 1st element
public:
darray(int size)
{
n = size;
a = new int[n];
}
~darray(){ delete[] a; }
void get_input();
int get_element(int index);
void set_element(int index, int value);
int count(){ return n; }
void print();
};
void darray::get_input()
{
for (int i = 0; i < n; i++)
{
cin >> *(a + i);
}
}
int darray::get_element(int index)
{
if (index == -1)
index = n - 1;
return a[index];
}
void darray::set_element(int index,int value)
{
a[index] = value;
}
void darray::print()
{
for (int i = 0; i < n; i++)
{
cout << a[i];
if (i < (n - 1))
cout << " ";
}
cout << endl;
}
// perform insertion sort on the array a
void insertion_sort(darray d)
{
int v = d.get_element(-1); // v is the right-most element
int e = d.count() - 1; // pos of the empty cell
// shift values greater than v to the empty cell
for (int i = (d.count() - 2); i >= 0; i--)
{
if (d.get_element(i) > v)
{
d.set_element(e,d.get_element(i));
d.print();
e = i;
}
else
{
d.set_element(e, v);
d.print();
break;
}
}
}
int main()
{
int s;
cin >> s;
darray d(s);
d.get_input();
insertion_sort(d);
system("pause");
return 0;
}
I use the darray class to make a array of size n at runtime. This class gives basic functions to handle this array.
This programs says debugging assertion failed at the end.
It gives this error after ruining the program.Other than that the program works fine. What is the reason for this error ?
You need to declare and define a copy constructor:
darray::darray(const darray& src)
{
n = src.n;
a = new int[n];
for (int i = 0; i < n; i++)
{
*(a + i) = *(src.a + i);
}
}