getch() in C++

[neoak]

I don't know what to do next. I write all my programs, and they run fine. However, my teacher asked for one condition: That all programs must ask at the end if you want them to repeat (like a reload without closing the window).

A normal code:

Code: Select all

#include "iostream.h"
#include "math.h"
#include <stdio.h>
#include <conio.h>

int main()
{

double A,Xold,Xnew;
double d=1;

cout << "Enter the number which square root will be determined";
cin >> A;

Xold=A;

while (d>0.000001;)
{
Xnew=(Xold+(A/Xold))/2;
d=fabs(Xnew-Xold);
Xold=Xnew;
}

cout << "The Square Root of the number is: " << Xnew << "\n";

return 0;
}

This code works. However, my teacher wants the code like this:

Code: Select all

#include "iostream.h"
#include "math.h"
#include <stdio.h>
#include <conio.h>

int main()
{

double A,Xold,Xnew;
double d=1;
char key='y';

do
{
cout << "Enter the number which square root will be determined";
cin >> A;

Xold=A;

while (d>0.000001;)
{
Xnew=(Xold+(A/Xold))/2;
d=fabs(Xnew-Xold);
Xold=Xnew;
}

cout << "The Square Root of the number is: " << Xnew << "\n";

cout << "\nDo you wish to run this program again? Press Y for yes, N for no:";
key=getch();
cout << "\n";
}

while(key=='s'||key=='S');

return 0;
}

The problem is the "getch()". Anyone here knows how to use getch() in C++?, because if i use plain C, it would work (but i like more C++). However, i want to now.

[q_006]

you don't need a getch()

you can easily use cin and char.

example

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char choice;
choice = 'y';
while (choice == 'Y' || choice 'y') {
     cout << "Loop still runs << endl;
     cin >> choice;
}

also since you're using C++, it'll be better to use:

Code: Select all

<iostream>
<cmath>
<cconio>   // you may have to use conio.h depending on compiler
using namespace std;

hope this helps.
(and hope i didn't break a rule...)

[toastman]

Actually there is a significant difference. cin will wait for the 'Enter' key to be pressed, while getch doesn't.
getch should still work the same. C++ pretty much includes all of C.

[neoak]

Actually, cin was one of the solutions. However, a condition was that you mustn't press Enter to get the program to run again.

toastman, the problem is that it compiles in VC++ 6.0, but it goes wrong after it begins to do the operations after asking the values. Could you please try it?

[Mask of Destiny]

The standard C IO doesn't get allong with C++ IOStream. If you're going to use getch, you need to use printf and scanf instead of cin and cout.

[ATani]

Actually, cin was one of the solutions. However, a condition was that you mustn't press Enter to get the program to run again.

try:

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char foo = cin.get();

Based on the book "C++ How To Program" by "H.M. Deitel & P.J. Deitel" this should read one character at a time. You can also use:

Note that cin.get() does not block, it will return EOF when there is no input.

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char charArray = new char[10];
cin.get(charArray, 10);

This example will read up to 10 characters but not more than 10.

[neoak]

See next post.

[neoak]

The problem was using \n for new lines. Just use endl and it will work like a charm.