solve the complex numbers and do operations on it

//complex numbers .cpp
// 
//***** **********::Header files::********** *******

#include<iostream>
#include <windows.h>//for set_color & clear_screen/.
#include<iomanip>// for setw() maipulator .
#include<cmath> //for square root .
#include<windows.h>
using namespace std;

//************::Variables of the program::*************
const double pi=3.14159265358979323846264;// the constant PI
double re1,re2,im1,im2,re3,im3;//(re1,im1)first num(re2,im2)second num(re3,im3)result.
double deno;//for division.
int count;// the counter of your choise (add,subtr,...).
double r1,r2;//the modulus under the root.
char choise,sign1,sign2,i1,i2;//for the question (y/n)/sign of the num +i or -i.

//********* ****::complex structure::*** *******************
struct complex
{
	double x,y;   //x real , y imagin .
};

//*********::setTextColor fn decleration::*************
void setTextColor(short fgColor, short bgColor);
//******* ***::setCursorPosition fn decleration::******* *******
void setCursorPosition(short row, short col);
//****** *****::clearScreen fn decleration::********* ******
void clearScreen();

int add();
int subtract();
int multiply();
int divide();
int conjugate();
int angle_theta();
int modulus();
int convert_tri();
int convert_pol();
int convert_expon();
int main()
{	//the body of the program.
	setTextColor(15,0);
	cout<<setw(48)<<"Cairo university\n"<<setw(58)<<"Faculty of compters and information\n";
	cout<<"\n"<<setw(58)<<"************************************\n\n";
	cout<<setw(55)<<"\"C O M P L E X   N U M B E R S\" \n"<<setw(55)<<"*******************************\n\n";
	cout<<"this program to solve the complex numbers (Addition , Substruction , Multiplication , Division , Contugate , Angle(theta) , Modulus ).\n\n";
	do
	{
number1:		cout<<"\tEnter the first complex number : ";
				cin>>re1>>sign1>>i1>>im1;
			if(sign1!='+')
			{
				if(sign1!='-')
				{
					cout << "\tOnly + and - are allowed.\n" << endl;
					goto number1;
				}
			}

			
			if(i1!='i')
			{
				cout << "\tOnly Letter 'i' is allowed.\n" << endl;
				goto number1;
			}
			


number2:		cout<<"\tEnter the second complex number : ";
				cin>>re2>>sign2>>i2>>im2;

			if(sign2!='+')
			{
				if(sign2!='-')
				{
					cout << "\tOnly + and - are allowed.\n" << endl;
					goto number2;
				}
			}


			if(i2!='i')
			{
				cout << "\tOnly Letter 'i' is allowed.\n" << endl;
				goto number2;
			}
		do
		{
menu:		clearScreen();
			cout<<endl<<setw(45)<<"\"MAIN MENU\"\n";
			cout<<setw(45)<<"===========\n";
			cout<<"1) Addition"<<setw(45)<<"2) Subtraction\n";
			cout<<"3) Multiplication"<<setw(36)<<"4) Division\n";
			cout<<"5) Conjugate"<<setw(45)<<"6) Angle(theta)\n";
			cout<<"7) Modulus"<<setw(66)<<"8) Transform to trigenometric form\n";
			cout<<"9) Transform to polar form"<<setw(49)<<"10) Transform to Exponential form\n";
			cout<<"Your choise = ";
			cin>>count;
			clearScreen();
			switch(count)
			{
			case 1://Addition
				cout<<endl<<setw(45)<<"\"Addition\"\n\n";
				add();
				break;
			case 2://Subtraction
				cout<<endl<<setw(46)<<"\"Subtraction\"\n\n";
				subtract();
				break;
			case 3://Multiplication
				cout<<endl<<setw(48)<<"\"Multiplication\"\n\n";
				multiply();
				break;
			case 4://Division
				cout<<endl<<setw(45)<<"\"Division\"\n\n";
				divide();
				break;
			case 5://Conjugate
				cout<<endl<<setw(45)<<"\"Conjugate\"\n\n";
				conjugate();
				break;
			case 6://Angle(theta)
				cout<<endl<<setw(47)<<"\"Angle(theta)\"\n\n";
				angle_theta();
				break;
			case 7://Modulus
				cout<<endl<<setw(45)<<"\"Modulus\"\n\n";
				modulus();
				break;
			case 8://Transform to trigenometric form
				cout<<endl<<setw(56)<<"\"Transform to trigenometric form\"\n\n";
				convert_tri();
				break;
			case 9://Transform to polar form
				cout<<endl<<setw(52)<<"\"Transform to polar form\"\n\n";
				convert_pol();
				break;
			case 10://Transform to Exponential form
				cout<<endl<<setw(55)<<"\"Transform to Exponential form\"\n\n";
				convert_expon();
				break;
			default ://when the user enter anumber more than 10 .
				cout<<setw(46)<<"\"Out of Menu\"\n\n";
				cout<<"\t\tError  ! enter from 1 to 10 only \n\n";
				goto menu;
			}
			cout<<"Do you want to perform another operation on your numbrs?(y/n)";
			cin>>choise;//to do another operation or not.
		}while(choise=='y'||choise=='Y');
		cout<<"Do you want to enter anew numbers?(y/n)";
		cin>>choise;//to enter anew numbers or not.
		clearScreen();
	}while(choise=='y'||choise=='Y');
	return 0;
}

//**** ******::setTextColor fn defination::******* *************
void setTextColor(short fgColor, short bgColor)
{
	HANDLE hConsole = GetStdHandle ( STD_OUTPUT_HANDLE );
	SetConsoleTextAttribute ( hConsole, fgColor | (bgColor << 4) );
}

//*** **::setCursorPosition fn defination::******** **********
void setCursorPosition(short row, short col)
{
	HANDLE hConsole = GetStdHandle ( STD_OUTPUT_HANDLE );
	COORD pos = {row, col};
	SetConsoleCursorPosition ( hConsole, pos );
}

//****** **::clearScreen fn defination::***** *********
void clearScreen()
{
	HANDLE hConsole = GetStdHandle( STD_OUTPUT_HANDLE );
	COORD topLeft = {0,0};
	FillConsoleOutputCharacter(hConsole, ' ', 25*80, topLeft, NULL);
	setCursorPosition(0, 0);
}
int add()
{
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	re3=re1+re2;
	im3=im1+im2;
	if(im3<0)
		cout<<"\n\tZ1 + Z2 = "<<re3<<" - i "<<im3/-1<<endl;
	else
		cout<<"\n\tZ1 + Z2 = "<<re3<<" + i "<<im3<<endl;
	return 0;
}
int subtract()
{
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	re3=re1-re2;
	im3=im1-im2;
	if(im3<0)
		cout<<"\n\tZ1 - Z2 = "<<re3<<" - i "<<im3/-1<<endl;
	else
		cout<<"\n\tZ1 - Z2 = "<<re3<<" + i "<<im3<<endl;	
	return 0;
}
int multiply()
{
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	re3=(re1*re2)-(im1*im2);
	im3=(re1*im2)+(re2*im1);
	if(im3<0)
		cout<<"\n\tZ1 * Z2 = "<<re3<<" - i "<<im3/-1<<endl;
	else
		cout<<"\n\tZ1 * Z2 = "<<re3<<" + i "<<im3<<endl;
	return 0;
}
int divide()
{
	if(sign1=='+')
	{
		if(sign2=='+')
		{
			re3=(re1*re2)+(im1*im2);
			im3=(-re1*im2)+(re2*im1);
		}
		if(sign2=='-')
		{
			re3=(re1*re2)-(im1*im2);
			im3=(re1*im2)+(re2*im1);
		}
	}
	if(sign1=='-')
	{
		if(sign2=='-')
		{
			re3=(re1*re2)+(im1*im2);
			im3=(re1*im2)-(re2*im1);
		}
		if(sign2=='+')
		{
			re3=(re1*re2)-(im1*im2);
			im3=(-re1*im2)+(-re2*im1);
		}
	}
	deno=(re2*re2)+(im2*im2);
	
	if(im3<0)
		cout<<"\n\tZ1 / Z2 = "<<re3<<"/"<<deno<<" - i "<<im3/-1<<"/"<<deno<<endl;
	else
		cout<<"\n\tZ1 / Z2 = "<<re3<<"/"<<deno<<" + i "<<im3<<"/"<<deno<<endl;
	return 0;
}
int conjugate()
{
	if(sign1=='-')
	{
		sign1='+';
		cout<<"\tThe conjugate of the first number = "<<re1<<sign1<<im1<<endl;
	}
	else
	{
		sign1='-';
		cout<<"\tThe conjugate of the first number = "<<re1<<sign1<<i1<<im1<<endl;
	}
	if(sign2=='-')
	{
		sign2='+';
		cout<<"\tThe conjugate of the first number = "<<re2<<sign2<<i2<<im2<<endl;
	}
	else
	{
		sign2='-';
		cout<<"\tThe conjugate of the first number = "<<re2<<sign2<<im2<<endl;
	}
		
	return 0;
}
int angle_theta()
{
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	float g,h;
	cout<<"\tThe angle of the first number\xE9 = ";
	g=atan(im1/re1);
	g=(g*180)/pi;
	if(g<0)
		g*=-1;
	if(re1>0&&im1>0)
		g=g;
	else if(re1<0&&im1>=0)
		g=180-g;
	else if(re1<0&&im1<0)
		g=180+g;
	else if(re1>=0&&im1>0)
		g=360-g;
	cout<<g<<endl;
	cout<<"\tThe angle of the second number\xE9 = ";
	h=atan(im2/re2);
	h=(h*180)/pi;
	if(h<0)
		h*=-1;
	else if(re2>0&&im2>0)
		h=h;
	else if(re2<0&&im2>0)
		h=180-h;
	else if(re2<0&&im2<0)
		h=180+h;
	else if(re2>0&&im2>0)
		h=360-h;
	cout<<h<<endl;
	return 0;
}
int modulus()
{
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	cout<<"\tThe modulus of the first number (r)= ";
	r1=((re1*re1)+(im1*im1));
	cout<<"root"<<(r1)<<endl;
	cout<<"\tThe modulus of the second number (r)= ";
	r2=((re2*re2)+(im2*im2));
	cout<<"root"<<(r2)<<endl;
	return 0;
}
int convert_tri()
{
	float g,h;
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	r1=((re1*re1)+(im1*im1));
	r2=((re2*re2)+(im2*im2));
	g=atan(im1/re1);
	g=(g*180)/pi;
	if(g<0)
		g*=-1;
	if(re1>0&&im1>0)
		g=g;
	else if(re1<0&&im1>=0)
		g=180-g;
	else if(re1<0&&im1<0)
		g=180+g;
	else if(re1>=0&&im1>0)
		g=360-g;
	h=atan(im2/re2);
	h=(h*180)/pi;
	if(h<0)
		h*=-1;
	else if(re2>0&&im2>0)
		h=h;
	else if(re2<0&&im2>0)
		h=180-h;
	else if(re2<0&&im2<0)
		h=180+h;
	else if(re2>0&&im2>0)
		h=360-h;
	cout<<"the first number = "<<"root"<<r1<<"(cos "<<g<<" + "<<"i"<<" sin "<<g<<" ).\n";
	cout<<"the second number = "<<"root"<<r2<<"(cos "<<h<<" + "<<"i"<<" sin "<<h<<" ).\n";
	return 0;
}
int convert_pol()
{
	float g,h;
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	r1=((re1*re1)+(im1*im1));
	r2=((re2*re2)+(im2*im2));
	g=atan(im1/re1);
	g=(g*180)/pi;
	if(g<0)
		g*=-1;
	if(re1>0&&im1>0)
		g=g;
	else if(re1<0&&im1>=0)
		g=180-g;
	else if(re1<0&&im1<0)
		g=180+g;
	else if(re1>=0&&im1>0)
		g=360-g;
	h=atan(im2/re2);
	h=(h*180)/pi;
	if(h<0)
		h*=-1;
	else if(re2>0&&im2>0)
		h=h;
	else if(re2<0&&im2>0)
		h=180-h;
	else if(re2<0&&im2<0)
		h=180+h;
	else if(re2>0&&im2>0)
		h=360-h;
	cout<<"the first number = "<<"root"<<r1<<"<"<<g<<endl;
	cout<<"the second number = "<<"root"<<r2<<"<"<<h<<endl;
	return 0;
}
int convert_expon()
{
	float g,h;
	if(sign1=='-')
		im1*=-1;
	if(sign2=='-')
		im2*=-1;
	r1=((re1*re1)+(im1*im1));
	r2=((re2*re2)+(im2*im2));
	g=atan(im1/re1);
	g=(g*180)/pi;
	if(g<0)
		g*=-1;
	if(re1>0&&im1>0)
		g=g;
	else if(re1<0&&im1>=0)
		g=180-g;
	else if(re1<0&&im1<0)
		g=180+g;
	else if(re1>=0&&im1>0)
		g=360-g;
	h=atan(im2/re2);
	h=(h*180)/pi;
	if(h<0)
		h*=-1;
	else if(re2>0&&im2>0)
		h=h;
	else if(re2<0&&im2>0)
		h=180-h;
	else if(re2<0&&im2<0)
		h=180+h;
	else if(re2>0&&im2>0)
		h=360-h;
	cout<<"the first number = "<<"root"<<r1<<"e^i"<<g<<endl;
	cout<<"the second number = "<<"root"<<r2<<"e^i"<<h<<endl;
	return 0;
}