calc with loop

[36k1hbRD]

I've made a calculator program but I can't get it to work with loops. So I have to rerun it everytime. Can someone give me some example source code.

[Mats]

Can we see your code so far?

[Ceset]

yes could we see your code

but if you want here is a possible usage

while(someValue != someNumber)
{
    //program
}

[36k1hbRD]

`

[Ceset]

everything seems fine(i m assuming code mistakes caused by iPhone). just put your code except definitons in a while loop and make a query.
like:

types values;
while(x != someValue)
{
    //your code
}

[36k1hbRD]

//can you add it to this one for me as an example.

#include <iostream>

int main()
{
    using namespace std;
    cout << "enter a number: \n";
    int x;
    cin >> x;
    cout << "\n";
    cout << "\n";
    cout << "1 = multiplication  ";
    cout << "2 = division  ";
    cout << "3 = addition  ";
    cout << "4 = subtraction  ";
    cout << "-----------------------------------------------------------------------------------------\n";
    cout << "enter your choice: \n";
    char o;
    cin >> o;
    cout << "enter your last number: \n";
    int y;
    cin >> y;
    if ((o = 1))
        cout << x * y;
    else if ((o = 2))
        cout << x / y;
    else if ((o = 3))
        cout << x + y;
    else if ((o = 4))
        cout << x - y;
    else
        cout << "you entered an invalid operator\a";
    return 0;
}

[Ceset]

#include <iostream>

//    writing this line here would be better
//instead of inside main().
using namespace std;

int main()
{
    //    for beautiful coding
    //always add your declarations
    //to the beginning.
    char o;
    int x;
    int y;

    //    it will keep looping as long
    //as x isnt equal to -1.
    while(x != -1)
    {
        cout << "enter a number: \n";
        cin >> x;
        cout << "\n";
        cout << "\n";
        cout << "1 = multiplication  ";
        cout << "2 = division  ";
        cout << "3 = addition  ";
        cout << "4 = subtraction  ";
        cout << "-----------------------------------------------------------------------------------------\n";
        cout << "enter your choice: \n";
        cin >> o;
        cout << "enter your last number: \n";
        cin >> y;
        if ((o = 1))
            cout << x * y << endl;
        else if ((o = 2))
            cout << x / y << endl;
        else if ((o = 3))
            cout << x + y << endl;
        else if ((o = 4))
            cout << x - y << endl;
        else
            cout << "you entered an invalid operator\a";
    }

    return 0;
}

i m not changing it much since i assume you are a beginner. but try to develop this one it will help you a lot.

and go through for and while loops. and if necessery more previous topics

[36k1hbRD]

im learning from c++ primer plus for about two weeks but I learned a lot of basics online before

[36k1hbRD]

theres one problem my code above and i dont know whats wrong. the answer always multiplying the 2 numbers even if i use division

[Ceset]

good thing knowing it wasnt your homework :D. i m relieved

[36k1hbRD]

try it in your compiler. it always multiplies the 2 numbers

[Ceset]

wow i never realized. there are some mistakes. sorry

fixed one:

#include <iostream>

//    writing this line here would be better
//instead of inside main().
using namespace std;

int main()
{
    //    for beautiful coding
    //always add your declarations
    //to the beginning.
    char o;
    int x;
    int y;

    //    it will keep looping as long
    //as x isnt equal to -1.
    while(x != -1)
    {
        cout << "enter a number: \n";
        cin >> x;
        cout << "\n";
        cout << "\n";
        cout << "1 = multiplication  ";
        cout << "2 = division  ";
        cout << "3 = addition  ";
        cout << "4 = subtraction  ";
        cout << "-----------------------------------------------------------------------------------------\n";
        cout << "enter your choice: \n";
        cin >> o;
        cout << "enter your last number: \n";
        cin >> y;
        //it should be == instead of =
        //haha sorry i didnt realized it :D
        if ((o == 1))
            cout << x * y << endl;
        else if ((o == 2))
            cout << x / y << endl;
        else if ((o == 3))
            cout << x + y << endl;
        else if ((o == 4))
            cout << x - y << endl;
        else
            cout << "you entered an invalid operator\a";
    }

    return 0;
}

note : "==" is a query while "=" is an assignment.

[ajh32]

Create a class say CCalc, and then while the instance of your class is not NULL continue running the program:

int main (int argc, char* argv[])
{
    do
    {
         // instantiate instance of your CCalc, say a singleton:
         CCalc* pCal = CCalc::GetInstance();
         // do calculations etc...
         // then when user switches calculator off its destructor is called
         // and pCal is deleted and NULL assigned to pointer
    } while (pCal);

    return 0;
}

HTH

[Ceset]

@ajh32 well i doubt he would be able to do that couse he said he just started two weeks ago

[ajh32]

@Ceset - well at least have a do{} while(condition); loop that keeps looping until the condition is false and then exits.

[Ceset]

well i see no reason about you are being worng but also no reason for me too. it is like chosing the percantage of the milk in a chocolate chosing between do{}while() and while() for a beginner

[36k1hbRD]

thanks @Ceset