I still do not have much knowledge in C ++, I would like to ask for help for a task. I must create a stack, which is filled with data entered by the keyboard and the entire stack to write in external stack. I have made functions push, pop and simple program that displays the stack but before that data must be written in an external file. Can anybody help me with the external file?
#include <iostream>
#include <iomanip>
#include <stdlib.h>
using namespace std;
struct elem
{ int key; elem *next;} *start=NULL, *p;
void push(int n)
{
p=start;
start=new elem;
start->key=n;
start->next=p;}
int pop(int &n){
if (start)
{
n=start->key;
p=start;
start=start->next;
delete p;
return 1;
}
else
return 0;
}
int main(){
int num;
cout<<"Input integers:"<<setw(10);
while (cin>>num)
{
push(num);
}
cout<<endl<<"Stack:"<<endl;
while(pop(num))
{
cout<<num<<endl;
}
return 0;
}
//you can use this pseudocode
ofstream outFile;
while(start!=-1){
outFile << pop() << endl;
Related
Here is the whole code.
I know that the problem is somewhere in the hozzaad function, but I don't know to debug it.
I want to create a dynamic 2d array, with exacly vagonszam columns, but the number of rows differ.
#include <iostream>
#include <fstream>
#include <string.h>
#include <cstdlib>
using namespace std;
class Vonat{
int vagonszam, maxtomb;
int **vagonok;
int *seged;
enum szallitmany {szen, fa, ko} ;
public:
void beolvas(int x);
Vonat(): vagonszam(0), maxtomb(0) {}
void kiir();
void hozzaad(int **vagonok, int i, string szallitmany);
};
void Vonat::hozzaad(int **vagonok, int i, string szallitmany)
{
++vagonok[i][0];
seged = (int *) realloc(vagonok[i], ((vagonok[i][0]+1)*sizeof(int)));
seged[vagonok[i][0]]=1;
}
void Vonat::beolvas(int x)
{
char szovegesallomany[]="beVagonTartalma";
szovegesallomany[15]=x+'0';
szovegesallomany[16]='\0';
strcat(szovegesallomany, ".txt");
ifstream f(szovegesallomany);
f>>vagonszam>>maxtomb;
vagonok = new int*[vagonszam];
string szallitmany;
for(int i=0;i<vagonszam;i++)
{
vagonok[i] = new int[1];
vagonok[i][0]=0;
do
{
f>>szallitmany;
cout<<szallitmany<<" ";
hozzaad(vagonok, i, szallitmany);
}
while(szallitmany!="*");
}
f.close();
}
void Vonat::kiir()
{
cout<<vagonszam<<" "<<maxtomb<<endl;
}
int main()
{
Vonat v_52164;
v_52164.beolvas(1);
v_52164.kiir();
Vonat v_54587;
v_54587.beolvas(2);
v_54587.kiir();
return 0;
}
In this code something's wrong, because after running it gets the error message specified before.
Thanks to everyone, who try to help me, all the best.
whenever I run the program, there is no output, the program just ends. Am i doing something wrong? I'm sure there's something i missed but i can't seem to figure it out.
#include <iostream>
#include <string>
using namespace std;
class Addr
{
public:
Addr(int i = 0){
total = i;
}
void addNum(int num){
total += num;
}
int getNum(){
return total; }
friend int print(Addr& var);
private:
int total;
};
int print(Addr& var){
return var.total;
}
int main()
{
Addr object1;
object1.addNum(3);
print(object1);
return 0;
}
Your program behaves correctly. There is no output because you are not printing anything to the console in your program.
The print function merely returns the total.
If you wish to print the value to the console then you could for example change the definition as follows:
int print(Addr& var){
cout << var.total << endl; // this prints to the console output
return var.total;
}
There is no issue with your code. The fact is that no print function is used. I have modified your main function.
int main()
{
Addr object1;
object1.addNum(3);
cout<<print(object1);
return 0;
}
So I am trying to call a function in my main.cpp file but I get "error: no matching function for call to 'Queue::Queue()."
Queue.h
#ifndef QUEUE_H
#define QUEUE_H
#include <iostream>
class Queue
{
public:
Queue(int);
~Queue();
//circular queue methods
void enqueue(std::string);
std::string dequeue(); //should send through network, call transmit msg
void printQueue();
bool queueIsFull(); //send when full
bool queueIsEmpty(); //send when empty
protected:
private:
int queueSize;
int queueHead;
int queueTail;
int queueCount;
std::string *arrayQueue;
};
#endif // QUEUE_H
Queue.cpp
#include "Queue.h"
#include <iostream>
#include <fstream>
#include <sstream>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
using namespace std;
Queue::Queue(int qs)
{
queueSize = qs;
arrayQueue = new string[queueSize];
queueHead = 0;
queueTail = 0;
}
Queue::~Queue()
{
delete[] arrayQueue;
}
void Queue::enqueue(string word)
{
for (int i=0;i<10;i++)
{
arrayQueue[i] = word;
}
}
void Queue::printQueue()
{
for(int j=0;j<10;j++)
{
cout<<arrayQueue[j]<<endl;
}
}
main.cpp
#include <iostream>
#include "Queue.h"
using namespace std;
int main()
{
int userChoice;
Queue q;
while(2==2)
{
cout<<"======Main Menu======"<<endl;
cout<<"1. Enqueue word"<<endl;
cout<<"2. Dequeue word"<<endl;
cout<<"3. Print queue"<<endl;
cout<<"4. Enqueue sentence"<<endl;
cout<<"5. Quit"<<endl;
cin>>userChoice;
if (userChoice == 1)
{
string enqueueWord;
cout<<"word: ";
cin>>enqueueWord;
enqueue(enqueueWord);
}
if (userChoice == 2)
{
}
if (userChoice == 3)
{
}
if (userChoice == 4)
{
}
if (userChoice == 5)
{
}
}
return 0;
}
So to call the function from the header file I did "Queue q;" at the beginning of the int main() and then when I needed to call the function I did "q.enqueue(enqueueWord)." I also tried just doing "Queue::enqueue(enqueueWord), but that also didn't work and I get a different error. I feel like this is an easy fix but I just can't figure it out. Thanks for the help and feel free to ask me to clarify anything.
Queue q;
attempts to call the default constructor Queue::Queue. However, this constructor has been removed automatically since you explicitly declare a constructor, namely Queue::Queue(int), on your own.
Pass an appropriate argument to q when initialized, like
Queue q1(42); // pre-C++11 syntax
Queue q{42}; // available since C++11
(Note: 42 is only an exemplary value here.)
You could also use default arguments to keep the definition as-is and initialize the object with a default value.
Notes:
Why while(2==2)? while (true) is the common way.
For my current assignment, I have to use the following header file,
#ifndef STACK_H
#define STACK_H
template <class T, int n>
class STACK
{
private:
T a[n];
int counter;
public:
void MakeStack() {
counter = 0;
}
bool FullStack() {
return (counter == n) ? true : false ;
}
bool EmptyStack() {
return (counter == 0) ? true : false ;
}
void PushStack(T x) {
a[counter] = x;
counter++;
}
T PopStack() {
counter--;
return a[counter];
}
};
#endif
To write a program that will take a sentence, store it into the "stack", and then display it in reverse, and I have to allow the user to repeat this process as much as they want. The thing is, I am NOT allowed to use arrays (otherwise I wouldn't need help with this), and am finding myself stumped.
To give an idea of what I am attempting, here is my code as of posting, which obviously does not work fully but is simply meant to give an idea of the assignment.
#include <iostream>
#include <cstring>
#include <ctime>
#include "STACK.h"
using namespace std;
int main(void)
{
auto time_t a;
auto STACK<char, 256> s;
auto string curStr;
auto int i;
// Displays the current time and date
time(&a);
cout << "Today is " << ctime(&a) << endl;
s.MakeStack();
cin >> curStr;
i = 0;
do
{
s.PushStack(curStr[i]);
i++;
} while (s.FullStack() == false);
do
{
cout << s.PopStack();
} while (s.EmptyStack() == false);
return 0;
} // end of "main"
UPDATE
This is my code currently
#include <iostream>
#include <string>
#include <ctime>
#include "STACK.h"
using namespace std;
time_t a;
STACK<char, 256> s;
string curStr;
int i;
int n;
// Displays the current time and date
time(&a);
cout << "Today is " << ctime(&a) << endl;
s.MakeStack();
getline(cin, curStr);
i = 0;
n = curStr.size();
do
{
s.PushStack(curStr[i++]);
i++;
}while(i < n);
do
{
cout << s.PopStack();
}while( !(s.EmptyStack()) );
return 0;
You're on the right track, but you shouldn't be looping until the stack is full -- there are no guarantees curStr consists of at least 256 characters. Instead, loop like as follows...
int n = curStr.size();
do {
s.PushStack(curStr[i++]);
} while (i < n);
Now, you should really not write <bool-expr> == false or <bool-expr> == true... instead, merely write !<bool-expr> and <bool-expr>, respectively. You don't need all of your auto storage specifiers on the local variables, either. Your professor should also look into using the constructor rather than using MakeStack.
edit: It appears you had some trouble translating my code. You only need to i++ once per loop -- this increments our position in the string. As you are doing it now, you are actually incrementing the position twice and thus only pushing every other character.
Use a linked list instead of array in stack.
In the linked list, always store the tail pointer of your list's last node. Each node maintains a reference to your prev node.
A <--- B <---- C (tail)
push:
A <--- B <---- C <---- D (tail)
pop:
A <--- B <---- C (tail)
// D is popped out
when the tail == null, you know it is an empty stack
Hello i'm trying to program the addition of 2 matrices into a new one (and it does when i run the program step by step) but for some reason VS 2010 gives me an access error after it does the addition.
Here is the code.
#include <iostream>
#include <cstdio>
#include <conio>
using namespace std;
class operatii
{
typedef double mat[5][5];
mat ms,m1,m2;
int x1,x2,y1,y2;
public:
void preg();
int cit_val();
void cit_mat(int&,int&,double[5][5]);
void suma();
void afisare(int&,int&,double[5][5]);
};
void operatii::preg()
{
cit_mat(x1,y1,m1);
cit_mat(x2,y2,m2);
suma();
afisare(x1,y1,ms);
}
int operatii::cit_val()
{
int n;
cin>>n;
return n;
}
void operatii::cit_mat(int& x,int& y,double m[5][5])
{
char r;
cout<<"Matrice patratica? Y/N ";
cin>>r;
if ((r=='y')||(r=='Y'))
{
cout<<"Numar linii si coloane: ";
x=cit_val();
y=x;
}
else
{
cout<<"Numar linii: ";
x=cit_val();
cout<<"Numar coloane: ";
y=cit_val();
}
for (int i=1;i<=x;i++)
for (int j=1;j<=y;j++)
cin>>m[i][j];
}
void operatii::suma()
{
if ((x1==x2)&&(y1==y2))
for (int i=1;i<=x1;i++)
for (int j=1;i<=y1;j++)
ms[i][j]=m1[i][j]+m2[i][j];
else cout<<"Eroare";
}
void operatii::afisare(int& x,int& y,double m[5][5])
{
cout<<endl;
for (int i=1;i<=x;i++)
{
for (int j=1;j<=y;j++)
cout<<m[i][j];
cout<<endl;
}
}
void main()
{
operatii matrice;
matrice.preg();
system("PAUSE");
}
Any kind of help would be apreciated.
Arrays are 0-based in c++.
Change your various variants of for (somevar=1; somevar<=something) to for (somevar=0; somevar<something)
You're writing past the end of your arrays, which overwrites stack return address, leading to a return to nonexecutable code, again leading to an access violation.
Also,
for (int j=1;i<=y1;j++)
I think you want to use j not i here. Such errors are much easier to see if you use longer and more distinct variable names than "i" and "j", such as e.g. "Line" and "Column"