Squaring numbers

[SomeCodingNoob]

Still practicing basic code, wrote something to square a number inputted by the user, but some values (e.g. 5, 10, 11, 13, 15, 20) come out as the squared number -1, any help would be very welcomed.

#include <iostream>
#include <cmath>

using namespace std;

int squareNumber ()
{
    cout << "Enter number to be squared: " << endl;
    int x;
    cin >> x;
    return pow(x,2);
}

int main ()
{
    cout << "Your number squared is: " << squareNumber () << endl;
    return 0;
}

[Chervil]

but some values (e.g. 5, 10, 11, 13, 15, 20) come out as the squared number -1

That's probably due to truncating the floating-point value when it is converted to an integer. Why does this matter? Well, the pow() function typically will calculate the logarithm of x, multiply that by the required power, and then calculate the antilogarithm. Thus the result may be approximate, such as 24.99999995 or something.

At any rate, all that number-crunching is a huge overkill when all that is required is to multiply x by itself.

[SomeCodingNoob]

I was just trying to be purposely awkward to aid the learning process, thanks :)

[giblit]

CodeWizKid wrote:

I was just trying to be purposely awkward

Well you did a good job at making it awkward when you did

Your number squared is: Enter number to be squared: 10
100

I think it would look much more cleaner like

Please enter a number to be squared: 10
10 squared is 100

You could do this by something like:

1 2 3 4 5 6 7 8 9 10 11

#include <iostream> int main() { std::cout << "Please enter a number to be squared: "; int numberToBeSquared = 0; //I prefer to initialize std::cin >> numberToBeSquared; //also good to give good variable names std::cout << numberToBeSquared << " squared is " << numberToBeSquared * numberToBeSquared << std::endl; return 0; }

Please enter a number to be squared: 10 10 squared is 100

*fixed code tags

[xenovia12]

the codes is working well to me

[SomeCodingNoob]

Thanks very much for the advice giblit :)

[SomeCodingNoob]

Just to be awkward again though, why would something like this not work? It says numberToBeSuared was not declared in this scope.

#include <iostream>

using namespace std;

int squareNumber ()
{
cout << "Enter number to be squared: " << endl;
int numberToBeSquared;
cin >> numberToBeSquared;
return numberToBeSquared*numberToBeSquared;
}

int main ()
{
cout << numberToBeSquared << " squared is " << squareNumber () << endl;
return 0;
}

[wildblue]

numberToBeSquared is defined locally in the squareNumber function - the main function won't know what it is when you try to print it out here

cout << numberToBeSquared << " squared is " << squareNumber () << endl;
return 0;

[SomeCodingNoob]

Okay that makes sense, how do I go about fixing it?

[Chervil]

Declare the variable in main(), pass it to the function. return a result from that function.

Example:

#include <iostream>

using namespace std;
    
int doubleNumber(int n)
{   
    return n * 2;
}

int main()
{
    int x = 0;
    cout << "Enter x value to be doubled: " << endl;
    cin >> x;
    cout << "Double " << x  << " is: " << doubleNumber(x) << endl;
    return 0;
}

[xenovia12]

you could also do this

squared(n)