Help with if else statements

[LGoh]

I've been facing the problem in which an error message: In function 'int main()': 16:1: error: 'else' without a previous 'if'. I've included an "if" on line 11 but the error message continues to show up. Could anyone please give me some advise on how to alter the coding?

#include<iostream>
#include<sstream>
using namespace std;
int main()
{
float r, result, h;

cout<<"volume of cylinder, please insert radius:\n";
cin>>r;
result=3.1415926535*r*r;
if(r<0);
{
do (r<0); while (r<0); {cout<<"Number entered is negative. Please insert another non-negative integer: \n";
cin>>r;
}
else;
{
cout<<"Area of circle is "<<result<<". Please insert Height: \n";
cin>>h;

if (h<0) {cout<<"Number entered is negative. Please insert another non-negative integer: \n";
cin>>h;
result=result*h;
cout<<"The volume of the cylinder is "<<result<<".";}
else (h>0);
{
result=result*h;
cout<<"The volume of the cylinder is "<<result<<".";}
}}}

[TarikNeaj]

Hey! In the future, please put all your code between code tags , they are under the format section <> - http://www.cplusplus.com/articles/jEywvCM9/


You're getting the error because
You have a lot of semicolons on the wrong places. And using loops wrong.

if (r<0)
	{
	do (r<0) while (r<0); {cout << "Number entered is negative. Please insert another non-negative integer: \n";
		cin >> r;
	}

Change it to

while (r < 0) {
			cout << "Number entered is negative. Please insert another non-negative integer: \n";
			cin >> r;
	}

Then just do this

if (r >= 0)
	{
		cout << "Area of circle is " << result << ". Please insert Height: \n";
		cin >> h;

		if (h<0) 
		{
			cout << "Number entered is negative. Please insert another non-negative integer: \n";
			cin >> h;
			result = result*h;
			cout << "The volume of the cylinder is " << result << ".";
		}
		else (h>0);
		{
			result = result*h;
			cout << "The volume of the cylinder is " << result << "."; 
		}

	}

It looks like you dont quite know how loops and if statements work. I suggest watching the tutorials on them here -

https://www.youtube.com/playlist?list=PLAE85DE8440AA6B83

[LGoh]

Thanks a bunch!

[TarikNeaj]

My pleasure :)

[kevinkjt2000]

You have semicolons (;) after the if on line 11, the else on line 16. Get rid of those semicolons.
Also on line 25, I see an else with a boolean condition. If statements must take this form:

if (condition1) {
    //statements...
} else if (condition2) {
    //statements...
} //....
else if (conditionN) {
    //statements...
} else {
    //statements...
}

All of the else if clauses and the else clause are optional.