loops

[LEHCAR95]

Hi, quick question for a brand new c++ user. How would i go about making a loop from 1 to a value which will be entered by the user (i will not know the value when programming.) Probably obvious but i've only just started this language. Thanks!

[Code Apperentice]

#include <iostream>

using namespace std;

void main()
{
int number;
cout << "Enter a number: " << endl;
cin >> number;
while(number > 0)
{
cout << number << " of Loops left" << endl;
number--;
}

This?

[LEHCAR95]

For example, i want a program to run and print the square roots of the numbers. I want the user to enter a number, and run the program from 1 to that number and printing out the numbers from 1 to the user input and beside them the square roots?

[Code Apperentice]

Yeah just put the code in the while loop

[LEHCAR95]

this is what i have but it's not working

#include <iostream>

using namespace std;

int main()
{

	int y;
	cout << "Enter any value :" ;
	cin >> y;
	
	while (y>0)
	{
	int square, powerr, powerrr;

	square = sqrt(y);
	powerr = y^2;
	powerrr = y^3;

	cout << "x" << "\t" << "sqrt" << "\t" << "x^2" << "\t" << "x^3" << "\t"   << "\n" 
		<< "===================" << "\n" 
		<< y << "\t" << square << "\t" << powerr << "\t" << powerrr;
	}

		int hold=0;
		return(0);
		cin>>hold;



}

[booradley60]

You must do something to y so it won't be the same value forever. Otherwise, your while condition will always be true. Notice that in Code Apperentice's example he has number--; at the end of his loop. That way, eventually the while condition will be false and the loop will end.

[wildblue]

Since you'll know how many times you'll want to repeat the loop based on the number the user enters, you could do this in a for loop, starting at 1 and running up to the user number.

I'd make the variable for square root a double, since you won't be dealing with integers in most cases for square roots. Also ^ is not used in C++ to raise a number to a power. There is a pow function in <cmath> but you could also just multiply the number by itself.

I pulled the header out of the loop so it only prints once.

int main()
{

	int usernumber, square, cube;
	double sqrt; //sqrt may not be integer value
	cout << "Enter any value :" ;
	cin >> usernumber;
	
	cout << "x" << "\t" << "sqrt" << "\t" << "x^2" << "\t" << "x^3" << << "\n" 
<< "===================" << "\n";
	for (int i=1;i<=usernumber;i++)
	{
	sqrt = sqrt(i);
	square = i*i; // not y^2;
	cube = i*i*i; //not y^3;
	cout << i << "\t" << sqrt << "\t" << square << "\t" << cube;
	}

	return 0;
}

[LEHCAR95]

thanks so much, the return 0 however isnt actually pausing the screen? would it be in with the for statement?

[wildblue]

return 0 isn't intended to pause the screen.

Are you trying to keep the console from closing after the program runs? There's a thread stickied at the top of this section that talks about that - http://www.cplusplus.com/forum/beginner/1988/

[LEHCAR95]

thanks!