Please check my code

[boost lexical cast]

Hey guys I'm a beginner in C++ (learning overloads and templates in tutorials). I made a small project and I would like you guys to have a look at it. Here is a snippet. Please tell me how to make it better and some constructive criticism. Thanks!!!
EDIT:
Here it is sorry. I didn't know how to show all code. This is a calculator. A calculator where you enter 2 sides of the right triangle and it figures out the missing side (Pythagorean Theorem).
I made the program restart by copying the code in int main () and pasting it in void restart (). I didn't use a loop because I kept running into problems. I cleared the screen with string (50, '\n'). But I'm pretty sure there are other better ways.

#include <iostream>
#include <math.h>
#include <string>
using namespace std;

void instructions()
{
	cout << "Instructions:\n";
	cout << "1. Enter length of 1st side of right\ntriangle.\n";
	cout << "2. Enter length of 2nd side of right\ntriangle.\n";
	cout << "3. The process of the calculation is shown and the final answer is the missing side\nlength.\n\n";
	cout << "Tips:\n";
	cout << "Press the \"enter\" key after you type\nsomething\n";
	cout << "Press \"more\" and press \"restart\" to do\nanother calculation\n";
	cout << "Press \"more\" and press \"toggle soft\nkeyboard\" to use keyboard\n";
	cout << "Press \"more\" and press \"preferences\" to\nchange settings like font size, text color,\netc\n\n";
	cout << "IMPORTANT:\n";
	cout << "Only numbers will be accepted!\nAnything else will cause a\ncalculation error!\n\n";
}
void restart()
{
	cout << string (50, '\n');
    int a, b;
    string exit;
    
    cout << "[ Pythagorean Theorem Calculator ]\n(Right Triangle)\n\n";
	instructions();
    cout << "Length of 1st side of triangle: ";
    cin >> a;
    cout << "Length of 2nd side of triangle: ";
    cin >> b;
    
    a *= a;
    b *= b;
    double pyth;
    pyth = sqrt(a+b);
    
    cout << endl;
    cout << "a^2 + b^2 = c^2" << endl;
    cout << sqrt(a);
    cout << "^2";
    cout << " + ";
    cout << sqrt(b);
    cout << "^2";
    cout << " = ";
    cout << "?" << endl;
    cout << a;
    cout << " + ";
    cout << b;
    cout << " = ";
    cout << a + b << endl;
    cout << "SQRT of ";
    cout << a + b;
    cout << " is ";
    cout << sqrt(a+b);
    cout << "!" << endl;
    cout << endl;
    cout << "Missing side length: ";
    cout << pyth << '\n' << '\n';
    cout << "Type \"exit\" to exit and \"again\" to\ndo another calculation: ";
    cin >> exit;
    
    if(exit=="again")
    restart ();
    
    else
    cout << "Exiting...";
}
int main()
{
    int a, b;
    string exit;
    
    cout << "[ Pythagorean Theorem Calculator ]\n(Right Triangle)\n\n";
	instructions();
    cout << "Length of 1st side of triangle: ";
    cin >> a;
    cout << "Length of 2nd side of triangle: ";
    cin >> b;
    
    a *= a;
    b *= b;
    double pyth;
    pyth = sqrt(a+b);
    
    cout << endl;
    cout << "a^2 + b^2 = c^2" << endl;
    cout << sqrt(a);
    cout << "^2";
    cout << " + ";
    cout << sqrt(b);
    cout << "^2";
    cout << " = ";
    cout << "?" << endl;
    cout << a;
    cout << " + ";
    cout << b;
    cout << " = ";
    cout << a + b << endl;
    cout << "SQRT of ";
    cout << a + b;
    cout << " is ";
    cout << sqrt(a+b);
    cout << "!" << endl;
    cout << endl;
    cout << "Missing side length: ";
    cout << pyth << '\n' << '\n';
    cout << "Type \"exit\" to exit and \"again\" to\ndo another calculation: ";
    cin >> exit;
    
    if(exit=="again")
    restart();
    
    else
    cout << "Exiting...";
    
    return 0;
}

[Computergeek01]

Please tell me how to make it better

Please tell us what it's supposed to do. You're structure could be called 'odd-ball' if this were surrealist art. Otherwise, it's a bit confusing there bud.

[E0p9LyTq]

What are the values for a and b?

a and b are not assigned any values, so use whatever garbage value is in the memory location.

[Computergeek01]

@FurryGuy: You're asking someone who is grasping at straws to explain why they are doing 'X'... Identify their purpose, then where they went wrong and THEN determine where they went askew.

[keanedawg]

Have you tried compiling your code yet?

That's always a good way to start

[boost lexical cast]

Sorry guys look at the code now. The code is a calculator. Enter 2 sides of a right triangle and it figures out the missing side. Pythagorean Theorem.

[Arslan7041]

Better to use a loop than to call the function recursively.

[Arslan7041]

And what do you mean using a loop THEN calling the function?

Sorry, that was my fault. Classic grammar mistake: I meant to write "than", not "then". Meaning, its superior to write all the code in the main function in a loop (if the user chooses to go again), rather than recursively calling the restart() function.

[TheIdeasMan]

http://www.cplusplus.com/doc/tutorial/

int main()
{
cout << "Hello";
main();
}

That's a troll tactic.

[boost lexical cast]

closed_account_5a8Ym39o6/
Difference between program_entry(); and return program_entry()???

[boost lexical cast]

So is this better?

int main()
{
    int a, b;
    string exit;
    
    do {
    cout << "[ Pythagorean Theorem Calculator ]\n(Right Triangle)\n\n";
	instructions();
    cout << "Length of 1st side of triangle: ";
    cin >> a;
    cout << "Length of 2nd side of triangle: ";
    cin >> b;
    
    a *= a;
    b *= b;
    double pyth;
    pyth = sqrt(a+b);
    
    cout << endl;
    cout << "a^2 + b^2 = c^2" << endl;
    cout << sqrt(a);
    cout << "^2";
    cout << " + ";
    cout << sqrt(b);
    cout << "^2";
    cout << " = ";
    cout << "?" << endl;
    cout << a;
    cout << " + ";
    cout << b;
    cout << " = ";
    cout << a + b << endl;
    cout << "SQRT of ";
    cout << a + b;
    cout << " is ";
    cout << sqrt(a+b);
    cout << "!" << endl;
    cout << endl;
    cout << "Missing side length: ";
    cout << pyth << '\n' << '\n';
    cout << "Type \"exit\" to exit and \"again\" to\ndo another calculation: ";
    cin >> exit;
    
    if(exit=="again")
    cout << string (50, '\n';
    
    else
    cout << "Exiting...";
    } while (exit=="again");

    return 0;
}

[TheIdeasMan]

closed account 5a8Ym39o6
WOW 6EQUJ5

Both of you are trolling.

[boost lexical cast]

@TheIdeasMan
How am I trolling?

[coder777]

@TheIdeasMan
You know that trolls are craving for attention, don't you?
So permanently jumping on the troll bandwagon just feeds the trolls...

[boost lexical cast]

@TheIdeasMan
@coder777
Alright!! What makes you guys think I'm trolling? I was just asking if I could call a function recursively using main();. If you look at my code it's not a troll at all. It's a pythagorean theorem calculator.

[coder777]

What makes you guys think I'm trolling?

I dont' think so. I want to remind TheIdeasMan not to feed trolls.

[boost lexical cast]

@coder777
Look. I'm the one who posted this question. I wanted to make my code better. And now you're calling my a troll... because TheIdeasMan said main(); was a troll tactic? Or maybe the fact I posted main();?

[Arslan7041]

@WOW 6EQUJ5:

The code you posted with the do-while loop seems correct. Only thing I would say is to call instructions() outside of the loop. No point in giving instructions to the user multiple times.

[JLBorges]

#include <iostream>
#include <string>
#include <cmath>
#include <iomanip>

void show_instructions()
{
	std::cout << "Instructions:\n"
	             "    1. Enter length of 1st adjacent side of right-angled triangle.\n"
	             "    2. Enter length of 2nd adjacent side of right-angled triangle.\n"
	             "    3. The process of the calculation is shown\n"
	             "       and the final answer is the length of the hypotenuse.\n\n";
}

double get_side( std::string side_name )
{
    std::cout << "\nenter a positive value for length of side '" << side_name << "': " ;

    double side ;
    if( std::cin >> side && side > 0 ) return side ; // valid input, return it

    // invalid input
    std::cout << "please enter a positive number\n" ; // inform the user
    std::cin.clear() ; // clear possible error because of non-numeric input
    std::cin.ignore( 1000000, '\n' ) ; // empty the input buffer
    return get_side(side_name) ; // and try again
}

void run_calculator()
{
    const double a = get_side( "one" ) ;
    const double b = get_side( "two" ) ;

    const double c = std::sqrt( a*a + b*b ) ;

    std::cout << std::fixed << std::setprecision(2) << "\n\n"
              << a << '*' << a << " + " << b << '*' << b << " == " << c << '*' << c
              << "\n\nlength of the hypotenuse: " << c << '\n' ;
}

bool again()
{
    std::cout << "\ntype 'again' to perform another calculation, 'exit' to exit: " ;

    std::string answer ;
    std::getline( std::cin >> std::ws, answer ) ; // std::cin >> std::ws skip leading white-space

    if( answer == "again" ) return true ;
    else if( answer == "exit" ) return false ;

    return again() ; // invaid input, try again
}

int main()
{
    show_instructions() ;

    do run_calculator() ; while( again() ) ;

    std::cout << "\nexit program.\n" ;
}

[coder777]

WOW 6EQUJ5 wrote:

And now you're calling my a troll...

I did not call you a troll and this is the last post regarding this.