ANSII problems with my program.

I have some problems with creating functions. I think I did everything right, but I can't figure out the problem. i will post the code. I know some of it might be incorrect now, but I will fix that later. I just need help with the functions.

Code:

//Bank Account Application

#include <stdio.h>
#include <iostream.h>
#include <conio.h>

addAccount()
{
	float addInput;
	cout<<"Enter the amount you wish to add to your account: ";
	cin>>addInput;
	
	return addInput;
}
subAccount()
{
	float subInput;
	cout<<"Enter the amount you wish to deduct from your account: ";
	cin>>subInput;
	
	return subInput;
}
interestAccount()
{
	float interest;
	cout<<"Enter your monthly interest rate: ";
	cin>>interest;
	
	float interestAdd;
	interestAdd=interest/accountBalance[numAccounts]*100;
	
	return interestAdd;
}
displayAccount()
{
	for(int i;i<numAccounts;i++)
	{
		cout<<"Information for account number "<<accountNumber[numAccounts]<<".";
		cout<<"Starting balance: "<<startBalance[numAccounts]<<"\n";
		cout<<"Currect balance: "<<accountBalance[numAccounts]<<"\n";
	}
}

main()
{
	//program description
	cout<<"Description.";
	
	int maxAccounts=10;
	
	for(int numAccounts=0;numAccounts<maxAccounts;numAccounts++)
	{
		char choice;
		cout<<"Enter 'N' for new account or 'V' to view account information.";
		cin>>choice;
		
		if(choice==v||choice==V)
		{
			//view account info
		}
		else
		{
			int accountNumber[numAccounts];
			cout<<"Enter account number: ";
			cin>>accountNumber[numAccounts];
			
			float startBalance[numAccounts];
			cout<<"Enter your currect account balance: ";
			cin>>startBalance[numAccounts];
			accountBalance[numAccounts]=startBalance[numAccounts];
			
			for(;;)
			{
				char choice2;
				cout<<"Enter 'D' to deposit or add money, 'W' to withdraw or deduct, 'I' to calculate interest, or 'X' to return to main menu.";
				cin>>choice2;
				
				if(choice2==x||choice2==X)
				{
					//return to main menu loop
					break;
				}
				else
				{
					switch(choice2)
					{
						case d:
							case D:
								//call function addAccount()
								accountBalance[numAccounts]=accountBalance[numAccounts]+addAccount();
								break;
								
								case w:
									case W:
										//call function subAccount()
										accountBalance[numAccounts]=accountBalance[numAccounts]-subAccount();
										break;
										
										case i:
											case I:
												//call function interestAccount()
												accountBalance[numAccounts]=accountBalance[numAccounts]+interestAccount();
												break;
												
												default:
													cout<<"You did not enter a 'D', 'W', or an 'I'.";
					}
				}
			}
		}
		if(choice2==x||choice2==X)
		{
			//go to top of main menu loop
			continue;
		}
		else
		{
		}
		
		if(choice==v||choice==V)
		{
			displayAccount();
		}
		else
		{
		}
		
		char choice3;
		cout<<"Enter 'C' to continue or 'X' to exit.";
		cin>>choice3;
		
		if(choice3==c||choice3==C)
		{
			//go to top of main menu loop
			continue;
		}
		else
		{
			switch(choice3)
			{
				case x:
					case X:
						//exit program
						break;
						
						default:
							cout<<"You did not enter a 'C' or an 'X'.";
			}
		}
	}
	return 0;
}

What I can see, you're comparing variables to characters wrong.

Code:

if(choice3==c||choice3==C)
{
	//go to top of main menu loop
	continue;
}

This could be implemented correctly, and much more neatly like this:

Code:

if (tolower(choice3) == 'c')
{
	//go to top of main menu loop
	continue;
}

You made this mistake throughout your entire program, as far as I can see.
And for the functions tolower and toupper you need to include <ctype.h>

Your functions don't have a return type defined.

In front of every function name you need a data type such as int, float, or void.

for example:

Code:

float addAccount()
{
     float addInput;
     cout<<"Enter the amount you wish to add to your account: ";
     cin>>addInput;

     return addInput;
}

For the displayAccount() function you will need a return type of void while the others would need a return type of float.

Also the main function should have a return type of int.