Programming Forums > Application Development > C++

Supreme · Jun 5th, 2005, 12:32 PM

I am a first year programming major. My teacher gave us a assignment where we have to have a prorgam use a sentinel-controlled reptition function. Now I get the loop to work properly no problem. My problem is with the sentinel value itself. When i type the sentinel value for the first statement it is supposed to end the loop however what ends up happening is i have to type the sentinel value for each of the input statements and then it will end. Please help

Here is the code:

#include

using std::cout;
using std::cin;
using std::endl;
using std::fixed;

#include

using std::setprecision;

int main()
{

int accnumber;
int counter;

double balance;
double credits;
double charges;
double limit;

balance = 0;
counter = 0;
credits = 0;

while ( accnumber != -1 ){

cout << "Enter account number (-1 to end): ";
cin >> accnumber;

cout << "Enter beginning balance: ";
cin >> balance;

cout << "Enter total charges: ";
cin >> charges;

cout << "Enter total credits: ";
cin >> credits;

cout << "Enter credit limit: ";
cin >> limit;

cout << fixed << setprecision( 2 );

balance = (balance + charges - credits);

cout << "Account: " << accnumber << endl;

cout << "Credit limit: " << limit << endl;

cout << "Balance: " << balance << endl;

if ( balance > limit )

cout << "Credit Limit Exceeded." << endl;

counter = counter + 1;

}

return 0;
}

Anyone who can figure out why this is doing this PLEASE explain to me what I did/ am doing wrong. I am trying to understand C++ to its fullest and don't want to cheat myself.

linuxman2k1 · Jun 5th, 2005, 2:02 PM

(Toggle Plain Text)

	cout << "Enter account number (-1 to end): ";
	cin >> accnumber;

try this

(Toggle Plain Text)

	cout << "Enter account number (-1 to end): ";
	cin >> accnumber;
	if(accnumber == -1){
		break;
	}

Supreme · Jun 5th, 2005, 2:47 PM

Quote:

Originally Posted by EverLearning

In the flow of the routine, once "break" is reached the loop automatically terminates regardless whether the condition, that makes the loop going, is met or not.
For example (even though it's not making much sense to do exactly smth. like this), in following code x == 10 will not occur as the loop will be terminated once y == 0;

(Toggle Plain Text)

x = 0;
y = 3;
while (x != 10)
{
   x = x + 1;
   y = y - 1;
   if (y == 0)
   {
       break;
    }
}

"continue" is an opposite equivalent.

Okay I used a break and it worked. thx guys I truly appreciate it. However I have a question now. If the sentinal value was set in thei while statment then why wasnt the sentinal value working as I assumed it would? Maybe my understanding of sentinal is faulty? Here is the corrected code, tell me what you guys think

Quote:

#include <iostream>

using std::cout;
using std::cin;
using std::endl;
using std::fixed;

#include <iomanip>

using std::setprecision;

int main()
{

int accnumber; // Account Number for each account
int counter; // number of accounts

double balance; // number with decimal point for balance
double credits; // number with decimal point for credits
double charges; // number with decimal point for charges
double limit; // number with decimal point for limit

balance = 0; // initialize balance
counter = 0; // initialize counter
credits = 0; // initialize credits

while ( accnumber != -1 ){ // set sentinal value

cout << "Enter account number (-1 to end): "; // prompt for input
cin >> accnumber;

if ( accnumber == -1 ){
break;
}

cout << "Enter beginning balance: "; // prompt for input
cin >> balance;

cout << "Enter total charges: "; // prompt for input
cin >> charges;

cout << "Enter total credits: "; // prompt for input
cin >> credits;

cout << "Enter credit limit: "; // prompt for input
cin >> limit;

cout << fixed << setprecision( 2 ); // allows floating point values to be printed

balance = (balance + charges - credits); // calculates balance to be used later

cout << "Account: " << accnumber << endl; // prints account number

cout << "Credit limit: " << limit << endl; // prints Credit Limit value

cout << "Balance: " << balance << endl; // prints calculation of balance

if ( balance > limit ) // condition if balance is greater than limit

cout << "Credit Limit Exceeded." << endl; // prints this statment when if statment is true

counter = counter + 1; // increments counter

}

return 0; // indicate successful termination
}

Wraith Daquell · Jun 5th, 2005, 2:53 PM

Not to be picky or anything, but the line:
[php]counter = counter + 1[/php]
would be better written:
[php]counter++[/php]

EverLearning · Jun 5th, 2005, 2:55 PM

Quote:

Originally Posted by Supreme

Okay I used a break and it worked. thx guys I truly appreciate it. However I have a question now. If the sentinal value was set in thei while statment then why wasnt the sentinal value working as I assumed it would? Maybe my understanding of sentinal is faulty? Here is the corrected code, tell me what you guys think

If i understand you correctly: you are asking why it did not work without the break?
Then it's because the condition of while-loop is not checked until the loop is completed. "Break" passes the control immediately to the statement following the loop, i.e. none of the stuff inside while-loop after "break" is going to execute.
If you are asking something else, please clarify

[edit]
sentinel simply means that some particular condition is reached, therefore routine should take some "other" action. Sentinel is also called a flag if that helps.

linuxman2k1 · Jun 5th, 2005, 2:56 PM

Quote:

Originally Posted by Supreme

However I have a question now. If the sentinal value was set in thei while statment then why wasnt the sentinal value working as I assumed it would?

This is because while will execute all statments in the loop before checking the sentinal value again

edit: EverLearning: you just beat me there

Supreme · Jun 5th, 2005, 3:01 PM

Quote:

Originally Posted by Wraith Daquell

Not to be picky or anything, but the line:
[php]counter = counter + 1[/php]
would be better written:
[php]counter++[/php]

wraith,

Does it help with performance or does it just look more professional? We just learned about counter++ in this chapter so I am not used to using it but I will from here on out.

Thank you,

EverLearning · Jun 5th, 2005, 3:02 PM

One quick suggestion:
instead of doing this:

(Toggle Plain Text)

int x;
x = 0;

you can just do this:

(Toggle Plain Text)

int x = 0;

@linuxman2k1: :p

Supreme · Jun 5th, 2005, 3:03 PM

Quote:

Originally Posted by EverLearning

If i understand you correctly: you are asking why it did not work without the break?
Then it's because the condition of while-loop is not checked until the loop is completed. "Break" passes the control immediately to the statement following the loop, i.e. none of the stuff inside while-loop after "break" is going to execute.
If you are asking something else, please clarify

[edit]
sentinel simply means that some particular condition is reached, therefore routine should take some "other" action. Sentinel is also called a flag if that helps.

ever learning no you hit it right on the head I understand completely. Was I not using the proper terminology when i explained my question? I hope to get a job in the programming field once im done with this degree. Should take 2 yrs from this point. Anyway just trying to master c++

I truly apprecaite all of your help. I am glad I found this place.

EverLearning · Jun 5th, 2005, 3:10 PM

Quote:

Was I not using the proper terminology when i explained my question?

I just wanted to be sure.

Quote:

I am glad I found this place.

Stick around ...

Jun 5th, 2005, 12:32 PM	#1
Supreme Newbie Join Date: Jun 2005 Posts: 8 Rep Power: 0	C++ homework problems PLEASE help [solved] I am a first year programming major. My teacher gave us a assignment where we have to have a prorgam use a sentinel-controlled reptition function. Now I get the loop to work properly no problem. My problem is with the sentinel value itself. When i type the sentinel value for the first statement it is supposed to end the loop however what ends up happening is i have to type the sentinel value for each of the input statements and then it will end. Please help Here is the code: #include using std::cout; using std::cin; using std::endl; using std::fixed; #include using std::setprecision; int main() { int accnumber; int counter; double balance; double credits; double charges; double limit; balance = 0; counter = 0; credits = 0; while ( accnumber != -1 ){ cout << "Enter account number (-1 to end): "; cin >> accnumber; cout << "Enter beginning balance: "; cin >> balance; cout << "Enter total charges: "; cin >> charges; cout << "Enter total credits: "; cin >> credits; cout << "Enter credit limit: "; cin >> limit; cout << fixed << setprecision( 2 ); balance = (balance + charges - credits); cout << "Account: " << accnumber << endl; cout << "Credit limit: " << limit << endl; cout << "Balance: " << balance << endl; if ( balance > limit ) cout << "Credit Limit Exceeded." << endl; counter = counter + 1; } return 0; } Anyone who can figure out why this is doing this PLEASE explain to me what I did/ am doing wrong. I am trying to understand C++ to its fullest and don't want to cheat myself. Last edited by Supreme; Jun 6th, 2005 at 10:47 AM.

Jun 5th, 2005, 2:02 PM	#2
linuxman2k1 Newbie Join Date: May 2005 Location: anonymous namespace Posts: 6 Rep Power: 0	(Toggle Plain Text) cout << "Enter account number (-1 to end): "; cin >> accnumber; cout << "Enter account number (-1 to end): "; cin >> accnumber; try this (Toggle Plain Text) cout << "Enter account number (-1 to end): "; cin >> accnumber; if(accnumber == -1){ break; } cout << "Enter account number (-1 to end): "; cin >> accnumber; if(accnumber == -1){ break; }

Jun 5th, 2005, 2:53 PM	#4
Wraith Daquell Programmer Join Date: Feb 2005 Location: Limbo Posts: 39 Rep Power: 0	Not to be picky or anything, but the line: [php]counter = counter + 1[/php] would be better written: [php]counter++[/php] __________________ The meek will inherit the earth. -WDaquell

Jun 5th, 2005, 3:02 PM	#8
EverLearning Hobbyist Programmer Join Date: May 2005 Location: Indiana Posts: 130 Rep Power: 4	One quick suggestion: instead of doing this: (Toggle Plain Text) int x; x = 0; int x; x = 0; you can just do this: (Toggle Plain Text) int x = 0; int x = 0; @linuxman2k1: :p __________________ got math? yumm... "All men by nature desire to know" -Aristotle, Metaphysics

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Programming Forums > Application Development > C++

C++ homework problems PLEASE help