C Arrays

1
C Arrays

• Dr. Ying Xie

2
Recap last class

• First OO program in C
• First multiple-file program in C

3

• //Account.h
• ifndef ACCOUNT_H
• define ACCOUNT_H
• include ltstringgt
• using namespace std
• class Account
• public
• //member functions
• Account()
• Account(string initID, string initPIN,
  double initBalance)
• void Deposit(double amount)
• int Withdraw(double amount)
• double GetBalance()
• string GetID()
• string GetPIN()

4

• //Account.cpp
• include"Account.h
• AccountAccount()
• balance 0
• id ""
• pin ""
• AccountAccount(string initID, string initPIN,
  double initBalance)
• id initID
• pin initPIN
• balance initBalance
• void AccountDeposit(double amount)
• balance amount

• int AccountWithdraw(double amount)
• if (balance gt amount)
• balance - amount
• return 0
• else
• return -1
• double AccountGetBalance()
• return balance
• string AccountGetID()
• return id

5

• //Client.cpp
• includeltiostreamgt
• include "Account.h"
• char showMenu()
• int login(Account)
• int main()
• double amount
• char request
• Account account1("00001", "aaaaa", 600.00)
• while (true)
• if (login(account1) 0)
• request showMenu()
• while(request! 'T')
• switch(request)
• case 'S'
• break

case 'D' cout
ltlt"PLease input the amount " cin gtgt
amount account1.Deposit(amount) break
case 'C' cout ltlt"\nYour current balance
is " ltlt account1.GetBalance() break
Default cout ltlt "Incorrect function
code entered. " break
//end of switch request
showMenu() //end of
while(request!T) //end of if
else cout ltlt "\n\nLogin failed, try
again! " ltlt endl //end of while //
to be continued
6

• //to continue
• int login(Account acc)
• string id, pin
• cout ltlt "\n\n"
• cout ltlt "Please type your id " ltlt endl
• cin gtgt id
• cout ltlt "Please type your pin " ltlt endl
• cin gtgt pin
• if ((acc.GetID() id)(acc.GetPIN()
  pin))
• return 0
• else
• return -1
• char showMenu()
• char request
• cout ltlt "\n\n------------function
  Menu----------------"

7

• //Client.cpp
• includeltiostreamgt
• include "Account.h"
• char showMenu()
• int login(Account)
• int main()
• double amount
• char request
• Account account1("00001", "aaaaa", 600.00)
• while (true)
• if (login(account1) 0)
• request showMenu()
• while(request! 'T')
• switch(request)
• case 'S'
• break

case 'D' cout
ltlt"PLease input the amount " cin gtgt
amount account1.Deposit(amount) break
case 'C' cout ltlt"\nYour current balance
is " ltlt account1.GetBalance() break
Default cout ltlt "Incorrect function
code entered. " break
//end of switch request
showMenu() //end of
while(request!T) //end of if
else cout ltlt "\n\nLogin failed, try
again! " ltlt endl //end of while //
to be continued
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C Arrays

• Static data structure consisting of related data
  items of the same type.
• Array of integer
• Array of character
• Array of accounts
• Why static data structure the size of an array
  remains the same throughout the program
  execution.
• Later on, we will introduce some of so-called
  dynamic data structure such as list, queues,
  stacks, whose size can grow and shrink as program
  executes.

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Array consecutive memory locations which share
the same name and store the same data type.
The ith element of this array is referred to as
ci-1.
Print out the sum of the first three elements of
array c cout ltlt c0 c1 c2 ltlt endl
x c6/2
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Use Array 1. Declare

• int c12
• int b100, x27
• Account acc_array100
• (default constructor will be called)

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Using Arrays 2. Initialization

• int arr110
• for (int i0 ilt 10 i)
• arr1i 0
• int arr25 32, 27, 64, 18, 95
• int arr36 0 ?

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• Account acc_array100
• How to initialize this one?

13

• accinfo.dat
• 00001 12345 600.00
• 00002 23456 1000.00
• 00003 34567 200.00
• 00004 45678 20000.00
• 00005 56789 100.00
• 00006 67890 30.00

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• includeltfstreamgt
• includeltstringgt
• include "Account.h"
• using namespace std
• int main()
• string id, pin
• double amount
• Account acc_array100
• int index -1
• ifstream accInfo("accInfo.dat")
• while(accInfo gtgt id gtgt pin gtgt amount)
• index
• Account acc(id, pin, amount)
• acc_arrayindex acc

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Using Arrays 3. Passing Array to a Function

• void modifyArray(int , int)
• int main()
• int arr15 0,1,2,3,4
• modifyArray(arr1, 5)
• void modifyArray(int b, int size)
• for (int i0 iltsize i)
• bi bi 2