Code help needed

Hello, iam making a atm to calculate some items. in the program i ask for a deposit and it does show. Then i as for balance which does show but at2x the variable i put in. I really have no clue as to what is causing the variable to multiple by 2 when i as for it to be seen in the account balance option.

Code:

#include<stdio.h>
#include<math.h>
int chooseaccounttype(void);
float Compound(float,int);
main()

{
	char select;
	float deposit=0,withdraw=0,sum1=0,sum2=0,interest=0;
	int accountchoice,months;
	do{
	printf("\n\n\n\ta)  Deposit");
	printf("\n\tb)  Withdraw");
	printf("\n\tc)  Add Interest");
	printf("\n\td)  Account Balance");
	printf("\n\te)  Exit");
	printf("\n\n\tPlease select one of the choices above (a -> e)");
	fflush(stdin);
	scanf("%c",&select);
	getchar();
	system("cls");
	
	
	switch (select)
		{
			case 'A':
			case 'a':
				printf("\n\n\tenter amount to deposit-->");
				fflush(stdin);
				scanf("%f",&deposit);
				fflush(stdin);
				system("cls");
				accountchoice=chooseaccounttype();
				printf("You deposited $ %.2f",deposit);
					getch();
					system("cls");
					break;
			case 'B':
			case 'b':
				printf("enter amount to withdraw");
				scanf("%f",&withdraw);
				system("cls");
				accountchoice=chooseaccounttype();
			break;
			case 'C':
			case 'c':
				printf("Enter the interest");
				scanf("%f",&interest);
				printf("\n Enter the amount of months");
				scanf("%i",&months);
				accountchoice=chooseaccounttype();
				getch();
			break;
			case 'D':
			case 'd':
				accountchoice=chooseaccounttype();
			break;
			case 'E':
			case 'e':
				printf("last check");
				getch();
			break;
		
			default:
				printf("\tinvalid Selection");
				getch();
				system("cls");
			break;
			}
	switch(accountchoice)
	{
	case 1:
		if(select=='a'||'A')
		{
			sum1= sum1+deposit;
		printf("Your new balance is %.2f",sum1);
		}
		else 
		if(select=='b'||'B')
		
			if(sum1<withdraw)
			{
				printf("Insuffient funds");
			}
			else if(sum1>=withdraw)
			{
		sum1=sum1-withdraw;
		fflush(stdin);
		printf("your new balance is %.2f",sum1);
		fflush(stdin);
		}

		else if(select=='c'||'C')
	{

		}
		else 
		{
			printf("u have %f",sum1);
			getch();
		}
		break;
	
	
	
	
	case 2: puts (" savings");
		break;
	}






	}while(select!='e' && select!='E');
}
	int chooseaccounttype(void)
	{
		int account;
			printf("\n\t\t1) Chequing"); 
			printf("\n\t\t2) Savings");
			printf("\n Please select the account type:");
			fflush(stdin);
			scanf("%i",&account);
			switch(account)
			{
			case 1:	
			return(1);
			break;	
			case 2: 
			return(2);
			break;
			}
			
	}

only account chequing is done for now so use that instead of savings. I cheacked my code long and i cant figure out what the problem is, any insight would be helpfull.

fflush(stdin) is failure #1: Cprogramming.com FAQ > Why fflush(stdin) is wrong

Code:

if(select=='a'||'A')

is failure #2. You cannot do compound boolean statements like that, you must be explicit:

Code:

if (select == 'a' || select == 'A')