C++ Help Coding Problem

[dana120864]

I am using Dev-C++ and my code isn't working. When I compile it it stops at the code C=A. The error message states that I don't have a header and the program doesn't recognize C=A. This is the question and I will give you what code I have.

I do not know what I am doing wrong. Help Please.

Write a program that declares 2 constants A and B, Initialize A=1 and B=2.2, Declare an int named C and a float named D, Initialize C=A and D=B, Write statements to print C and D to the screen

Ok here is my code:

// abcddec.cpp

// example of printing C and D

#include <iostream>

#include <cstdlib>

using namespace std;

int main()

{

int C;

C=A;

A=1;

float D;

D=B;

B=2.2;

cout << "C\n";

cout << "D\n";

system ("PAUSE")

return 0;

}

[Andre S. Veteran]

To validate input, you could define your length variable as an STL string. Then, iterate over each character in the string using the function isdigit() to verify that all characters are indeed digits. If you want to allow the user to retry if he made a mistake, your best bet is to make a while loop.

Here's my idea for a basic validation function :

#include <string>
#include <iostream>

using namespace std;

bool isValidEntry(string entry) {
	for (string::iterator it = entry.begin(); it != entry.end(); it++) {
		if (!isdigit(*it)) {
			return false;
		}
	}
	return true;
}

int main() {

	string entry;

	cout << "Welcome. Enter a number.";
	cin >> entry;
	if (isValidEntry(entry)) {
		cout << "Woohoo" << endl;
	}
	else {
		cout << "Noooo" << endl;
	}



	system("pause");
	return 0;
}

[dana120864]

To validate input, you could define your length variable as an STL string. Then, iterate over each character in the string using the function isdigit() to verify that all characters are indeed digits. If you want to allow the user to retry if he made a mistake, your best bet is to make a while loop.

Here's my idea for a basic validation function :

#include <string>
#include <iostream>

using namespace std;

bool isValidEntry(string entry) {
	for (string::iterator it = entry.begin(); it != entry.end(); it++) {
		if (!isdigit(*it)) {
			return false;
		}
	}
	return true;
}

int main() {

	string entry;

	cout << "Welcome. Enter a number.";
	cin >> entry;
	if (isValidEntry(entry)) {
		cout << "Woohoo" << endl;
	}
	else {
		cout << "Noooo" << endl;
	}



	system("pause");
	return 0;
}

I do like that but what I am looking for is when I type in the number or letter it goes ahead and calculates everything. Here is an example:

Enter SideA:

a

Enter SideB: (it won't let my type in SideB it just skips to the next line)

Enter SideC: (it won't let me type in SideC it just skips to the next line and calculates)

The Volume is 6

Here is my new code problems from above included:

#include <iostream>

#include <cstdlib>

using namespace std;

int main()

{

int SideA;

SideA = 1;

int SideB;

SideB = 2;

int SideC;

SideC = 3;

int volume;

// 1. Prompt for SideA

cout << "Enter SideA: " << endl;

// 2. Get SideA

cin >> SideA;

// 3. Prompt for SideB

cout << "Enter SideB: " << endl;

// 4. Get SideB

cin >> SideB;

// 5. Prompt for SideC

cout << "Enter SideC: " << endl;

// 6. Get SideC

cin >> SideC;

// 7. Calculate Volume

// Volume = SideA * SideB * SideC

int Volume = SideA * SideB * SideC;

// 8. Display Volume

cout << "The Volume is " << Volume << endl;

system ("PAUSE");

return 0;

}

[Andre S. Veteran]

Use a c-style string and cin.getline() for input. For instance:

char inputBuffer[256];

cout << "Enter first number";

cin.getline(inputBuffer, 256);

cout << "Enter second number";

cin.getline(inputBuffer, 256);

Now, you'll run in trouble if the user exeeds 256 characters, but let's keep this simple shall we? :p

Then convert to integer using atoi (in <cstdio>).

[dana120864]

Use a c-style string and cin.getline() for input. For instance:

char inputBuffer[256];

cout << "Enter first number";

cin.getline(inputBuffer, 256);

cout << "Enter second number";

cin.getline(inputBuffer, 256);

Now, you'll run in trouble if the user exeeds 256 characters, but let's keep this simple shall we? :p

Then convert to integer using atoi (in <cstdio>).

I got it to work thanks. :) What exactly does the inputBuffer[256] mean?

#include <iostream>

#include <cstdlib>

using namespace std;

int main()

{

int SideA;

SideA = 1;

int SideB;

SideB = 2;

int SideC;

SideC = 3;

char inputBuffer[256];

// 1. Prompt for SideA

cout << "Enter SideA";

// 2. Get SideA

cin.getline(inputBuffer, 256);

// 3. Prompt for SideB

cout << "Enter SideB";

// 4. Get SideB

cin.getline(inputBuffer, 256);

// 5. Prompt for SideC

cout << "Enter SideC";

// 6. Get SideC

cin.getline(inputBuffer, 256);

// 7. Calculate Volume

// Volume = SideA * SideB * SideC

int Volume = SideA * SideB * SideC;

// 8. Display Volume

cout << "The Volume is " << Volume << endl;

system ("PAUSE");

return 0;

}

[Andre S. Veteran]

char inputBuffer[256] declares an array of 256 characters named "inputBuffer". It's a C-style string, as opposed to a C++-style string. Unfortunately in C++ we generally need to use both and they work very differently. That was a world of confusion for me when I began (and still is, to a more limited extent).

Edited September 5, 2008 by Dr_Asik

[dana120864]

char inputBuffer[256] declares an array of 256 characters named "inputBuffer". It's a C-style string, as opposed to a C++-style string. Unfortunately in C++ we generally need to use both and they work very differently. That was a world of confusion for me when I began (and still is, to a more limited extent).

That makes sense thank you :)