I'm trying to implement a new datatype called HugeInteger in C++ with classes. I've encountered a problem that when I try to create new HugeInteger, my program terminates itself when the first number is printed. When I comment the statement the statement user enter a HugeInteger but the statement that displays the number is still there, the first number isn't written(the default value of the number is 0) and second number is filled by user. My try is as following:
HugeInteger.h
// HugeInteger class definition
#ifndef HUGEINT_H
#define HUGEINT_H
class HugeInteger
{
private:
int arr[40] = {0};
size_t len;
public:
void Input();
void Output();
};
#endif
HugeInteger.cpp
#include "HugeInteger.h"
#include <iostream>
#include <sstream> // to fill arr
void HugeInteger::Input()
{
std::string line;
int i;
std::getline(std::cin, line);
for (size_t i = 0; i < line.length(); i++)
{
arr[i] = line[i] - '0';
}
len = line.length();
}
void HugeInteger::Output()
{
int i = 0;
while (i < len)
std::cout << arr[i++];
}
main.cpp
#include <iostream>
#include "HugeInteger.h"
int main()
{
HugeInteger hui = HugeInteger();
//hui.Input(); // when this is commented, Output method does not work.
hui.Output();
HugeInteger hui2 = HugeInteger();
hui2.Input();
hui2.Output();
return 0;
}
Note: I've just perfomed another debug that I create another method called getLen so that I can access the len attribute. However, I put the code before and after Output method in the main.cpp, but I couldn't see the value of len neither these poisions. After that, I make the arr attribute as public, and tried to see the contents of it, and I couldn't see that either. I think my code doesn't work and I can somehow only see what I entered, after that the program is finished.
Note: I think I'm not facing a buffer overflow problem, because I always debugged my program with 3 4 digit numbers, so my array has contain 3-4 numbers and the rest is 0. Moreover, I'll probably put a code to handle this issue.
The call to Input() sets the value of the len member. Without the call, the member is uninitialized, but still used by Output().
Just initialize it to 0, similar to what you do with the array.
Related
I have been working on a project for my computer science class and have encountered an issue with the code working. I am shown no error except when I try to compile and I get an error that reads:
Exception thrown: write access violation.
_Left was 0xCCCCCCCC.
The purpose of my project is to take a list of names from an external file, read them into an array, sort said array and then output the sorted list all while using a class for the code.
Here is a copy of my code and I would like to extend my gratitude to whoever can help me through my issue:
**Header File**
#include <iostream>
using namespace std;
class person
{
public:
person();
bool get(ifstream&);
void put(ofstream&);
private:
int capacity = 0;
string first_name[CAPACITY];
string last_name[CAPACITY];
int age[CAPACITY];
};```
**Header function definitions cpp file**
#include<iostream>
#include<string>
#include<fstream>
#include<cstdlib>
const int CAPACITY=20;
using namespace std;
#include "Person.h"
//Names constructor
//Postcondition both first name and last name initialized to zero
person::person()
{
first_name[CAPACITY] = "";
last_name[CAPACITY] = "";
age[CAPACITY]=0;
}
bool person::get(ifstream& in)
{
in >> first_name[CAPACITY] >> last_name[CAPACITY] >> age[CAPACITY];
return(in.good());
}
void person::put(ofstream &out)
{
out << first_name[CAPACITY] << last_name[CAPACITY] << age[CAPACITY];
}
**cpp file which holds main**
#include<iostream>
#include<cstdlib>
#include<fstream>
#include<string>
const int CAPACITY = 20;
using namespace std;
#include "Person.h"
void pop(string *xp, string *yp);
void sort(string name[CAPACITY], int count);
int main()
{
class person names[CAPACITY];
ifstream infile;
ofstream outfile;
string filename;
string name[CAPACITY];
int n = 0;
cout << "Enter the file name you wish to open" << endl;
cin >> filename;
infile.open(filename + ".txt");
outfile.open("Person_New.txt");
if (infile.fail())
{
cout << "The file requested did not open" << endl;
exit(1);
}
while (!infile.eof())
{
names[n].get(infile);
n++;
}
sort(name, CAPACITY);
for (int i = 0; i < CAPACITY; i++)
{
names[i].put(outfile);
}
cout << "The file has been created" << endl;
infile.close();
}
void pop(string *xp, string *yp)
{
string temp = *xp;
*xp = *yp;
*yp = temp;
}
void sort(string name[CAPACITY], int count)
{
int i, j;
for (i = 0; i < count - 1; i++)
{
for (j = 0; j < count - i - 1; j++)
{
if (name[j] > name[j + 1])
{
pop(&name[j], &name[j + 1]);
}
}
}
}
Once again Thank you for any support
It sounds to me like the compiler is getting upset that you are trying to write (i.e. assign a value) at an address that you do not have permission to access. I believe your constructor for the class person might be at fault because of how this class stores its variables, as well as the class header:
Constructor for the class person:
`person::person(){
first_name[CAPACITY] = "";
last_name[CAPACITY] = "";
age[CAPACITY] = 0;
}`
Class header for the class person:
`class person{
public:
//stuff
private:
int capacity = 0;
std::string first_name[CAPACITY];
std::string last_name[CAPACITY];
int age[CAPACITY];
//more stuff
}`
C++ is very specific about its naming conventions, so it makes a distinction between capacity and CAPACITY. Because of this, the variable CAPACITY is not defined within the Person.h file.
Also, because CAPACITY is set to a fixed value in your Person.cpp file, whenever you use first_name[CAPACITY], last_name[CAPACITY], or age[CAPACITY] to assign new values, you are only updating the values at the index equal to CAPACITY unless you update the value of CAPACITY itself. In the code you provided, CAPACITY is equal to 20, so your program attempts to update exclusively index 20 with each method call. This will likely cause issues since the person class only attempts to make its arrays on the runtime stack, with a size of 0 each.
Separately, it seems like you want an array of people, but it appears that you are attempting to use a single person object to store the names and ages of multiple people by making these all arrays. Instead, I would recommend making first_name, last_name, and age not arrays, but rather single variables. Then, you can manipulate an array of type person using your CAPACITY variable. You got pretty close, but you can instead declare it as person myPersonArray[CAPACITY] (no need to mention "class" in front of it -- just be sure that you have #include "Person.h" in your main.cpp file). When you want to update a specific person, you can perform an operation like myPersonArray[updateThisIndexNum].update(newFirstName, newLastName, newAge) or some logical equivalent.
As a final note, I almost always highly recommend against using !infile.eof() to control your while loop when reading any file because eof() only indicates whether you have tried to read past the end of an input file. I would highly recommend checking out this post on Stack Overflow where people far more knowledgeable than I explain exactly why this is usually dangerous and how to avoid it.
I'm making a program to basically show the statistics about words the user enters. The rest of the program is fine so far, but I'm having a hard time adding words to a vector of type WordCount.
I have looked around and found several answers, which I would've thought could solve my issue, but I either get a very weird compiler error or it just does not work. I have tried using emplace_back and push_back with calls I thought was right. In essence, my problem code is as follows:
#include <iostream>
#include <string>
#include <vector>
using namespace std; //for simplicity here
struct WordCount {
string word;
int count;
//I have tried using this too:
WordCount(string _word, int _count) : word{_word}, count{_count} {}
};
//...//
void wordToVector(/**...**/,string addStr, vector<WordCount>& wordStats){
/**... code that I've tested to work; basically determined if the
word was already said as I need to have unique words only...**/
wordStats.push_back(WordCount(addStr, 1));
/** also tried: (some had "#include <istream>" when using emplace_back
but that didn't seem to make a difference for me in any case)
wordStats.emplace_back(WordCount(addStr, 1));
wordStats.emplace_back({addStr, 1});
wordStats.push_back(addStr, 1)
wordStats.push_back(addStr).word; (and wordStats.push_back(1).count;)
**/
}
int main() {
vector<WordCount> wordStats(1); //"1" to initialize the size
wordStats.at(0).word = "";
wordStats.at(0).count = 0;
/**There's already a part to change the first values to what they should
be, and it worked last I tested it. Below is a part was for my
personal use to see if anything came out... if it worked**/
for (int i = 0; i < 3; i++) {
cout << wordStats.at(i).word << endl;
cout << wordStats.at(i).count << endl;
}
return 0;
}
I must use a vector for this and cannot use pointers (as I've seen suggested) or #include <algorithm> per the instructions. If I typed in "Oh happy day!", it should be able to print (when fixed, with the current cout statements):
OH
1
HAPPY
1
DAY
1
(There's an earlier part that capitalizes every letter, which I tested to work).
This is my first post here because I'm lost. Please let me know if I provided too much or not enough. **Edited formatting
#include <iostream>
#include <string>
#include <vector>
using namespace std;
struct WordCount {
string word;
int count;
};
void wordToVector(string addStr, vector<WordCount>& wordStats){
for (int i = 0; i < wordStats.size(); i++) {
if (wordStats[i].word == addStr) {
wordStats[i].count = wordStats[i].count + 1;
return;
}
}
struct WordCount wc;
wc.word = addStr;
wc.count = 1;
wordStats.push_back(wc);
}
int main() {
vector<WordCount> wordStats;
wordToVector("hehe", wordStats);
wordToVector("hehe", wordStats);
wordToVector("haha", wordStats);
for (int i = 0; i < wordStats.size(); i++) {
cout << wordStats.at(i).word << endl;
cout << wordStats.at(i).count << endl;
}
return 0;
}
Using this code I get output:
hehe
2
haha
1
Is there anything else that needs to be added?
If you want to split the input by the spaces and check for occurrences of every word in the input it could be quite inefficient for longer texts to check for every word (Would be linear I think with M*N complexity), so if you are allowed I do suggest to use a map with word as key and value as the amount of occurrences - or something in that fashion.
I have a file that has been previously filled with data. The file consists of an array of structures. Each structure represents a round and each array position represents up to 20 rounds for an individual. My .h file:
define READTWENTY_H
class readTwenty {
public:
readTwenty();
void nonZeroes(int, int &);
struct a_round {
int score;
double course_rating;
int slope;
char date[15];
char place[40];
char mark[1];
}; //end structure definition
struct a_round all_info[20];
FILE *fptr;
}; //end class
#endif
In the data file some "rounds" have actual data in them and some have previously been filled with zeroes. I want to count the zero rounds. I have a loop in which I can ask for another "person" value to look at. This value is sent to a function in which the number of zero rounds is determined and returned by reference to a variable named "howMany".
// readMember.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
#include "readTwenty.h"
using namespace std;
int main()
{
int person = 0;
readTwenty personData;
int howMany = 0;
while (person != -999) {
cout << "Which member (keyfield) would you like to see? -999 to stop ";
cin >> person;
if (person == -999)
exit(0);
personData.nonZeroes(person-1, howMany);
cout << "The number of non-zero values for this member is " << howMany << endl;
}//end while
return 0;
}
Once sent to the nonzeroes function as "key" I create an offset into the file and read the 20 rounds for that individual and return by reference the value of count back to the calling routine into variable howMany.
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include "readTwenty.h"
#include <errno.h>
#include <cstdio>
readTwenty::readTwenty() {
const char *configfile;
configfile = "scores.dat";
#ifdef WIN32
errno_t err;
if((err = fopen_s(&fptr,configfile, "rb")) != 0)
#else
if ((fp_config = fopen(configfile, "rb")) == NULL)
#endif
fprintf(stderr, "Cannot open cinfig file %s!\n", configfile);
}//end constructor
void readTwenty::nonZeroes(int key, int &count) {
int zeroes = 0;
int offset = key * ((sizeof(all_info[0]) * 20));
fseek(fptr, offset, SEEK_SET);
for (int i = 0; i < 20; i++){
fread(&all_info[i], sizeof(all_info[0]), 1, fptr);
if (all_info[i].score == 0)
zeroes++;
all_info[i].mark[0] = ' ';
}//end for loop
count = 20 - zeroes;
fclose(fptr);
}//end of function nonZeroes
The problem is that the first value that I give for person comes back with the correct number of non-zero rounds. However, each succeeding iteration of the while loop regardless of the second value I give for person comes back with the same result as the first person? Would greatly appreciate any ideas you may have.
I currently have no computer to verify, but one line jumps out to me as it is a common error (for me at least):
The first param to your fread is &all_info[i]; you probably want &(all_info[i]), but this is not how the compiler understands it - & is stronger than [i], so you get (&all_info)[i].
You could also use all_info+i for the same effect.
This is my first time working with classes in C++ and I seem to be getting tripped up quite a lot. My program is supposed to be a rewrite of a previous program that used struct (see here: Random number generator in a for loop gives same numbers each time), but using a class instead.
#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;
const int WHEEL_POSITIONS = 30;
const char wheelSymbols[WHEEL_POSITIONS + 1] = "-X-X-X-X-X=X=X=X*X*X*X*X#X#X7X";
class slotMachine
{
private:
int spinPos;
char spinSymbol;
public:
slotMachine(); // Constructor
char symbols[WHEEL_POSITIONS + 1]; // Should be private?
void setSpinSymbol(); // Spins the wheels
char getSpinSymbol() const // Returns the symbol
{ return spinSymbol; }
} wheels[3];
// Constructor initializes slot wheels to contents of wheelSymbols
slotMachine::slotMachine()
{
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < (WHEEL_POSITIONS + 1); j++)
{
wheels[i].symbols[j] = wheelSymbols[j];
}
}
}
void slotMachine::setSpinSymbol()
{
for (int i = 0; i < 3; i++)
{
wheels[i].spinPos = (rand() % WHEEL_POSITIONS);
wheels[i].spinSymbol = wheels[i].symbols[(wheels[i].spinPos)];
}
}
void displayResults(slotMachine fwheels[3])
{
for (int i = 0; i < 3; i++)
{
cout << fwheels[i].getSpinSymbol();
}
}
void displayResults(slotMachine []);
//bool getWinner(slotMachine []);
int main(void)
{
slotMachine wheels[3];
time_t seed;
time(&seed);
srand(seed);
displayResults(wheels);
return 0;
}
The code compiles but outputs the following:
I have a feeling this error is caused by something having gone amiss in my constructor slotMachine, my getSpinSymbol() function, or my setSpinSymbol() function, but I've looked it over several times and can't seem to figure it out. I've read a handful of material online covering classes in C++, but I'm still very new and very shaky on the concept--apologies if it's something small or obvious that I've overlooked.
There are several issues with your code:
1.Class names should be started with upper case letter. slotMachine -> SlotMachine
2.Remove wheels[3] after class definition.You are using the array declared in main() method.
3.Why you are declaring displayResults(..) again after it's definition?
4.You are not calling setSpinSymbol() before displayResults(..).
The problem was explained to me by a friend not on StackOverflow, and I will transcribe his answer here in case anyone else (for any reason) runs into the same problem:
You aren't using constructors and methods correctly. You shouldn't be
accessing wheels (the array of slotMachine objects) directly inside
those methods; you should just be performing operations on "this," the
slotMachine object on which the method was called. For example, the
constructor slotMachine::slotMachine() is automatically called for
each element of the array wheels. You just need to initialize the
current slotMachine object inside the constructor:
slotMachine::slotMachine()
{
for (int j = 0; j < (WHEEL_POSITIONS + 1); j++)
{
this->symbols[j] = wheelSymbols[j];
}
}
And slotMachine::setSpinSymbol() should just set the value of
spinSymbol for the object on which the method was called:
void slotMachine::setSpinSymbol()
{
this->spinPos = (rand() % WHEEL_POSITIONS);
this->spinSymbol = symbols[this->spinPos];
}
(In all of this code, the this-> part is actually unnecessary; you
can leave it out if you want. I put it in to try to make it clearer
that these methods are operating on fields of "the current object.")
Now, the reason you are getting garbage is because you never call
setSpinSymbol(), so the spinSymbol field is never initialized in
these objects. You probably want to call setSpinSymbol() in the
constructor, so that the spinSymbol field is guaranteed to be
initialized.
This explanation did solve my problem, and my program now outputs the correct information, so I believe it to be correct. My issues with using constructors and methods correctly has been explained here, and the reason why I was getting garbage values (as well as a few other points) was answered by another commenter.
Okay - yes, this is homework, but it isn't mine. I have a friend taking an introductory C++ course who asked me for help, and I helped them write this program, but there is one weird bug that I can't figure out. Any helpful suggestions would be greatly appreciated. Thanks!!
The following is the code. The problem is that after the add_loop function, the int loop_size gets a random value. Within the function, it has the value it is supposed to have, but afterwards, it changes.
#include <iostream>
#include <string>
#include <stdlib.h>
#include <time.h>
using namespace std;
#define STRING_SIZE 50
void get_template (char StemLoop [])
{
char Template [STRING_SIZE];
cout<<"Please enter a template for the stem:";
cin>> Template;
strcpy (StemLoop, Template);
}
void add_loop (char StemLoop[], int loop_size)
{
char random_loop [STRING_SIZE];
int random_array[STRING_SIZE];
for (int i=0; i<loop_size; i++)
{
random_array[i] = rand() % 4;
if (random_array[i]==0)
random_loop[i]='A';
else if (random_array[i]==1)
random_loop [i]='U';
else if (random_array[i]==2)
random_loop [i]='G';
else if (random_array[i]==3)
random_loop [i]='C';
}
strcat (StemLoop, random_loop);
}
void add_complement(char StemLoop[], int loop_size)
{
int x =strlen(StemLoop);
int j=0;
char complement [STRING_SIZE]="";
for (int i=0; i<(x-loop_size); i++)
{
if (StemLoop[i]=='A')
complement[j]='U';
else if (StemLoop[i]=='U')
complement[j]='A';
else if (StemLoop[i]=='G')
complement[j]='C';
else if (StemLoop[i]=='C')
complement[j]='G';
j++;
}
strcat(StemLoop,complement);
}
void main()
{
int loop_size=0;
cout<<"Please enter the size of the loop: ";
cin>>loop_size;
char StemLoop [STRING_SIZE];
//Part1: the template
get_template (StemLoop);
//This is supposed to be the function that adds the loop of random "genes".
//It works, and within it the int loop_size is the correct value...
add_loop (StemLoop, loop_size);
/*...but here it is a random number. It's as if the random value generated
within the function is getting assigned to it. And of course, it's throwing off the
entire program.
*/
//Part#3: the complement
add_complement (StemLoop, loop_size);
cout<<"The complete stem-loop strand is:"<<StemLoop<<endl;
}
You're not 0-terminating random_loop before you use it in strcat, so strcat can write all over your stack. Try this:
random_loop[i] = 0;
strcat (StemLoop, random_loop);
A more serious problem could be that you're not checking you have enough room to strcat.