Time Conversion Calculator Help

[jennwenn25]

Hello,
I am trying to create a time conversion calculator and I think I have it down but I do not know how to get it to display just one answer per selection. Like I can select 1 and it shows results for 1 and 2 . . or I can select 3 and it says program terminated and it also shows results for 2. I'm sure it's something simple but I can't figure it out . . please help?

Thank you!

/* Specification:
This converts time  */

#include <iostream>

using namespace std;

namespace time{
     enum menuOptions {Minutes, Hours, Seconds, Modulus, Exit};
}

int main (){
         //ask the user for minutes
	   const int timeCalc = 60;
       int minutes = 0;
       int hours = 0;
       int seconds = 0;
       int modulus = 0;
       cout << endl << "Welcome to the Time Conversion Calculator!\n";
       cout << endl << "Enter minutes: ";
       cin >> minutes;
       cout << endl << endl;

        //ask the user for desired conversion method
        int convMeth = 0;

        cout << "Choose a conversion method:\n\n";
        cout << time::Hours << " - Minutes to hour(s) and minutes\n";
        cout << time::Seconds << " - Minutes to seconds\n";
        cout << "Make your selection: ";
        cin >> convMeth;
        
     //perform calculations and output result
        if (convMeth < 1 || convMeth > 2)
       {
        cout << endl << "Invalid choice - program terminated\n\n";
        }
        if (convMeth == 1)
       {
        hours = minutes / timeCalc;
        modulus = minutes % timeCalc;
        cout << endl << "Result:  " << minutes << " minutes equals "   << hours << " hour(s) and " << modulus << " minutes. \n\n";
        }
        if (convMeth = 2)
       {
        seconds = minutes * timeCalc;
        cout << endl << "Result:  " << minutes << " minutes equals " << seconds << " seconds. \n\n";
       }
            cout << endl << endl << "end of program\n\n";

return 0;
}

[mikiurban]

Line 44

if (convMeth = 2)

should be

if (convMeth == 2)

[mrnutty]

Do you understand this ?

if( something) { do something }

else if( it is something else ) { then do something else }

else if( it is something else) { then do something else }

[mikiurban]

The elses increase efficiency, but my point is " if (convMeth = 2) " always evaluates to true, so that if block will always execute. Adding elses in the existing code will definitely prevent both cases from executing, but if a third was later added, the logic would never get beyond the second test.

[mrnutty]

The elses increase efficiency, but my point is " if (convMeth = 2) " always evaluates to true, so that if block will always execute. Adding elses in the existing code will definitely prevent both cases from executing, but if a third was later added, the logic would never get beyond the second test.

Yep, so what are you trying to achieve again?

[mikiurban]

me? nothing, just trying to get jenn on the right track :)

[jennwenn25]

Line 44

if (convMeth = 2)

should be

if (convMeth == 2)

Yes that did it, thank you.

[jennwenn25]

Do you understand this ?

if( something) { do something }

else if( it is something else ) { then do something else }

else if( it is something else) { then do something else }

I do and I was trying to use the else and I couldn't get it to work for some reason . . I just started doing this a couple of weeks ago so bear with me.

I did change the = to == and everthing seemed to be fine . . I got the results I was looking for so that is good :)

[jennwenn25]

Yep, so what are you trying to achieve again?

I guess I am kind of confused as to when to use the if/else structure . . is it poorly written the way that I have done it??

I was just trying to get one result to print at a time . . kept getting 2 or all 3 (including program terminated) printing at the same time with any input I entered.

[mikiurban]

The difference between using "if/else" and using "if" multiple times is each "if" block gets checked all the time, and "if/else" will skip all remaining blocks after one of them resolves to true. For example, in this code:

int i = 0;
if (i < 1) // test a
{
    print("i is less than one!");
}
if (i < 2) // test b
{
    print ("i is less than 2!");
}

compare with:

int i = 0;
if (i < 1) // test c
{
    print("i is less than one!");
}
else if (i < 2) // test d
{
    print ("i is less than 2!");
}

In the "if/if" block, test a resolves to true, and prints out our message. Then, test b resolves true and prints our second message. In the "if/else" block, test c resolves true and prints our message. Test d is skipped, because the first one passed, so no second message gets printed.

Summary:
test a: resolves true, message printed
test b: resolves true, message printed
test c: resolves true, message printed
test d: skipped (because c passed), message not printed.

If we set i = 1 in both examples, then we get:
test a: resolves false, no message
test b: resolves true, message
test c: resolves false, no message
test d: not skipped (because c failed), message printed.

if/else is great when you want only one of the options processed. If it is possible for multiple matches, then use multiple ifs. Hope this helps!