Output wrong..

[Andrew V]

This is my code and i dont know why when i enter let's say x=3 and n=0 it gives 3.

#include <cstdlib>
#include <iostream>
 
using namespace std;
 
int main()                                                      
   {            
         printf("==========©©Andrei78©©==========");
         printf("=======©All Rights Reserved©====");
         printf("===========©05-06-2012©=========");                                                                       
       int count,x,u=1;                                           
       float n,y;                                             
 
       printf("Enter the values of x and n : ");               
       cin>>x>>n;               
       y = 1;                                                
       count = 1;        
do
 {                                                       
            y = y*x;                                           
            count++;           
 
       }        
while ( count <= n);                                        
 
       cout<<y;
       if(n=0){
            cout<<"1";
            }  
 
       system("PAUSE");
    return EXIT_SUCCESS;
}
 

[weaknessforcats]

This code:

           y = y*x;                                           
              count++;           
 
         }        
  while ( count <= n);   
 

When n is 0 and count is 1 then count<=n is really 1<=0, which is false so you drop out of the loop.

This time x=3 and y=1 so y*n is 1*3 which is 3.

You display 3.

Beyond that, this code:

if(n=0){
              cout<<"1";
              } 
 

assigns 0 to n, which will always be false. Probably you meant:

if(n==0){
              cout<<"1";
              } 
 

[Rabbit]

That's because a do while loop is guaranteed to run at least once. Use a while loop instead.

[Andrew V]

Got it.My bad i readed while and while but it was do-while and while sorry

[Andrew V]

Ok,i solved with positive and 0 powers.But now i am trying to do with negative power.I want it to show :
x=2
n=-1
y=0.5
i changed the code

while ( count <= n);

with

while ( count >= n);

but nothing happens.And when i am trying to put it with if(){} it gives the same number with the x(the base) with every number i enter

[divideby0]

You wouldn't need to change much; add a var to check whether or not the power is negative. If it is, multiply the power by -1 and use division instead of multiplication with the loop.

Always check against div by 0.

[weaknessforcats]

Remember, a negative power is calculated differetly from a positive power. You will need different logic inside your loop.

Plus, the loop control for -1 power needs to be +1 and the loop control for +1 power needs to be +1. I suggest you have a separate variable for your loop control.

[Andrew V]

Ok so i put

 while(n<0){

and then i put

 y = y*x;
      count--;
      cout<<y;       
 

but the output doesn't stop.I am working for like 6 hours at this project.Can u give me a hint?

[weaknessforcats]

First, before you get to your loop check to see if n is 0. If it is, skip the loop and display a 1. Anything to the 0th power is 1.

Second, if n is positive set your loop control variable to n.

Third, if n is negative, set your loop control variable to
-1 *n. So -3 will end up as 3 in the loop control variable.

Fourth, save the number in x.

Fifth, inside the loop calculate y = y * x.

Sixth, after you exit the loop check if n -s negative. If it is, your answer is 1/y. Otherwise, your answer is y.

Seventh, as to spending a ton of time, we once were where you are now. My story is that a barber once asked me what I did for a living. I said I was a C++ programmer. He said that sounded hard. I asked how long it took to become a barber. He said about 300 hours of class time plus 1800 hours of on-the-job haircutting. I thought, hmm 2100 hours. Full tme for year. Now I tell my students C++ programming is as easy as cutting hair -- after you spend 2100 hours practicing it. Good luck.

[Andrew V]

   while(count<=-1*n){

or

   while(n<0){

and then what?
how do i save a number..

[Mariostg]

@weaknessforcats
Nice Seventh. :)