Thread: Tell me about C/C++

Code:

#include <isostream>

using namespace std;

int main()
{
     int a, b, total;

     cout << "Enter two numbers here...;" << endl;

     cin >> a >> b;

     total= a + b;

     cout << "Sum equals;" <<Total << endl;

     system(PAUSE) ;

     return 0;
}

returns 7 errors fix it dreamviews!

Originally Posted by guitarboy

returns 7 errors fix it dreamviews!

Code:

/*#include <isostream>

using namespace std;*/

int main()
{
/*     int a, b, total;

     cout << "Enter two numbers here...;" << endl;

     cin >> a >> b;

     total= a + b;

     cout << "Sum equals;" <<Total << endl;

     system(PAUSE) ;
*/
     return 0;
}

Emmmm... doesn't that basically the actual code with :

Code:

int main()
{
     return 0;
}

?

I'm guessing that is some sarcastic way of saying his program can't be fixed?

Ok, I fixed it. Suck it, Ynot .

Code:

#include <iostream>
using namespace std;

int main()
{
     int a, b, Total;

     cout << "Enter two numbers here...;"

     ;cin >> a >> b;

     Total= a + b;

     cout << "Sum equals;" <<Total << endl;

     return 0;
}

I had no idea what I was doing, but it somehow worked

Yeah, C++ is case sensitive.

Originally Posted by guitarboy

Code:

#include <isostream>

It's supposed to be <iostream>, not <isostream> (input/output stream)

Edit: The compiler will also output which lines and expressions were making the trouble. Compiling that you'd first get an error stating that <isostream> couldn't be included in the project, and the subsequent errors came because std::cout and std::cin wasn't defined (the <iostream> header defines these values so you can use them)

I don't understand what it wrong with this. It says "error: expected primary-expression before "else"" and also "error: expected ';' before else"

It is supposed to be that it calculates the radius or circumfrence of a circle if you input the circumfrence/radius.

Have I done something wrong with the if/else thing?

Code:

#include <iostream>
using namespace std;

#define PI 3

int main()
{

double r, d, circle, entered_number;

cout<<"Enter 1 to find circumference, or enter 2 to find radius/diameter"<<endl;

if (entered_number == 1)
cout<<"To find circumfrence of circle, please input radius"<<endl;
cin>>r;
circle = PI * r * 2;
cout<<"The circumfrence of the circle is "<<circle<<endl;

else if (entered_number == 2)
cout<<"To find radius of circle, please input circumfrence"<<endl;
cin>>circle;
r = circle/(PI*2);
d = r * 2;
cout<<"The radius of the circle is "<<r<<" and diameter is "<<d<<endl;

    return 0;
}

EDIT: Fixed it, but there is something wrong somewhere in it, even though it runs... I'll need to find that.

EDIT2: found that problem too... a very obvious one

you've forgotten to group the code propperly. What you wrote is basically

Code:

#include <iostream>
using namespace std;

#define PI 3

int main()
{
double r, d, circle, entered_number;

cout<<"Enter 1 to find circumference, or enter 2 to find radius/diameter"<<endl;

if (entered_number == 1) {
cout<<"To find circumfrence of circle, please input radius"<<endl;
}
cin>>r;
circle = PI * r * 2;
cout<<"The circumfrence of the circle is "<<circle<<endl;
else if (entered_number == 2) {
cout<<"To find radius of circle, please input circumfrence"<<endl;
}
cin>>circle;
r = circle/(PI*2);
d = r * 2;
cout<<"The radius of the circle is "<<r<<" and diameter is "<<d<<endl;
    return 0;
}

When you wanted

Code:

#include <iostream>
using namespace std;

#define PI 3

int main()
{

double r, d, circle, entered_number;

cout<<"Enter 1 to find circumference, or enter 2 to find radius/diameter"<<endl;

if (entered_number == 1) {
cout<<"To find circumfrence of circle, please input radius"<<endl;
cin>>r;
circle = PI * r * 2;
cout<<"The circumfrence of the circle is "<<circle<<endl;

} else if (entered_number == 2) {
cout<<"To find radius of circle, please input circumfrence"<<endl;
cin>>circle;
r = circle/(PI*2);
d = r * 2;
cout<<"The radius of the circle is "<<r<<" and diameter is "<<d<<endl;
}
    return 0;
}

If you want more than one block of code after an if/else/for/while/whatever statement, you need to enclose it in brackets. Also, it's common to indent blocks so that the end result looks like this (but it's strictly optional, C/C++ ignores excess white space)

Code:

#include <iostream>
using namespace std;

#define PI 3

int main()
{
	double r, d, circle, entered_number;

	cout<<"Enter 1 to find circumference, or enter 2 to find radius/diameter"<<endl;

	if (entered_number == 1) {
		cout<<"To find circumfrence of circle, please input radius"<<endl;
		cin>>r;
		circle = PI * r * 2;
		cout<<"The circumfrence of the circle is "<<circle<<endl;
	} else if (entered_number == 2) {
		cout<<"To find radius of circle, please input circumfrence"<<endl;
		cin>>circle;
		r = circle/(PI*2);
		d = r * 2;
		cout<<"The radius of the circle is "<<r<<" and diameter is "<<d<<endl;
	}
	return 0;
}

Makes the code much cleaner, as you can see.

Yea, I had it all fixed up like that. And yea, all my indents went away while editing it so much, deleting, adding in stuff, I ended up deleting all the indents.

I could make the program much better than that, but right now, I'm just using it as a learning thing. Next thing to try is to use the loop thingy (do while?), so that the program stays open and you can calculate more.

You should also loop into while loops and for loops.

Code:

int a = 50;
do{
   std::cout << "I'm inside the loop " << a++ << std::endl;
} while (a < 10);

Code:

int a = 50;
while (a < 10){
   std::cout << "I'm inside the loop " << a++ << std::endl;
}

Have one but very important difference, see if you can figure out what it is

Well, one of them is a while loop, and one is a do while loop. I don't really understand the difference, even after reading about it.

I should look at this page on loops for ages. I have trouble taking in/reading that much information at once, mainly because of a short attention span. I'll just have to try...

Originally Posted by ninja9578

You should also loop into while loops and for loops.

Code:

int a = 50;
do{
   std::cout << "I'm inside the loop " << a++ << std::endl;
} while (a < 10);

Code:

int a = 50;
while (a < 10){
   std::cout << "I'm inside the loop " << a++ << std::endl;
}

Have one but very important difference, see if you can figure out what it is

The difference has to do with where the check is made. In the first bit of code, the check doesn't happen until after what's inside the loop has been done, therefore, it ALWAYs gets done at least once, the second piece of code does the check beforehand, so it may never get called

Stick with terminals for now, I'll show you how to make a window a little later.