do..while statement

[tricubix]

Hi friends, I'm a newbie into C/C++ world. So i hope you can help me with this question. I need to do a program using do..while statement in C languages to produce the following output


0 1
1 4
2 16
3 64
4 256
5 1024
6 4096

i have done something with this program and i only manage to get the following output

0 0
1 1
2 4
5 25

using this program :
[code=c]
#include<stdio. h>
int x=0;
int x2, x;
void main()
{
do
{

x2 = x;
x = x*x;
printf("\n%d %d", x2, x);
x += 1;
} while (x<=21);

getch();
}
[/code]
can anyone help me?

[ilikepython]

Hi friends, I'm a newbie into C/C++ world. So i hope you can help me with this question. I need to do a program using do..while statement in C languages to produce the following output


0 1
1 4
2 16
3 64
4 256
5 1024
6 4096

i have done something with this program and i only manage to get the following output

0 0
1 1
2 4
5 25

using this program :

#include<stdio. h>
int x=0;
int x2, x;
void main()
{
do
{

x2 = x;
x = x*x;
printf("\n%d %d", x2, x);
x += 1;
} while (x<=21);

getch();
}

can anyone help me?

Ok, so basically you need a variable to hold the left side (1, 2, 3 ...) and a variable to hold the right side (which I assume you multiple by 4 (1, 4, 16 ...)):
[code=cpp]
int count = 0; // left
int x = 1; // right

do {
printf("%d %d\n", count, x);
// now do whatever you need to get the next value for 'count' and 'x'
} while (count <= 21);
[/code]

[PieCook]

do
{
x2 = x;
x = x*x;
printf("\n%d %d", x2, x);
x += 1;
} while (x<=21);

One problem I noticed is that you have x = x*x inside your loop. In most cases, you should not modify the loop counter except while incrementing it, although there are a few peculiar exceptions, of course. I assume you meant to say x2 = x*x instead.

Now if you notice the mathematical relationship between each number in the left and the corresponding value on the right, you'll notice that they're not squares (2*2 != 16, 3*3 !=64, etc.), so x*x will not work.

Any computer scientist should be familiar with the powers of 2 (1,2,4,8,16,32, 64,128,256,512, 1024 at the minimum). It appears that all the required numbers in the right column are in our list (if you extend it to 1024,2048,4096) . So in your code, you should have some powers of 2. Don't forget to include the Math library.

[sicarie]

And you use getch() without declaring its library. Either remove getch() or run the risk of your teacher's compiler not being able to run your code and include conio.h.

[Ganon11]

Actually this doesn't look like powers of 2:

1, 4, 16, 64, 256, 1024, 4096...

Certainly, these are numbers that are powers of 2, but I'm not seeing 2, 8, 32, 128...etc. So that can't be the answer. What other patterns do you see?

[tricubix]

Ok, so basically you need a variable to hold the left side (1, 2, 3 ...) and a variable to hold the right side (which I assume you multiple by 4 (1, 4, 16 ...)):
[code=cpp]
int count = 0; // left
int x = 1; // right

do {
printf("%d %d\n", count, x);
// now do whatever you need to get the next value for 'count' and 'x'
} while (count <= 21);
[/code]

hi ilikepython, your note look great, but i still need your favour. As you provide me the coding i can't see what i have to put under the printf?? Really need your help as i really2 confuse right now. TQ in advanced

[tricubix]

Actually this doesn't look like powers of 2:

1, 4, 16, 64, 256, 1024, 4096...

Certainly, these are numbers that are powers of 2, but I'm not seeing 2, 8, 32, 128...etc. So that can't be the answer. What other patterns do you see?

what can i say that... 4 power to the left no.

4 power to 0 (left no) equal to 1
4 power to 1 (left no) equal to 4
4 power to 2 (left no) equal to 16
bla..bla..bla.. .ect..

i hope you can understand that..TQ

[Studlyami]

He gave you the answer

to hold the right side (which I assume you multiple by 4 (1, 4, 16 ...)

so take your left value and add one to it (x++)
take the right value and multiply it by 4.

also you initialize x twice.
int x=0;
int x2, x; //could reinitialize x so x would no longer be zero

the number on the left and the number on the right isn't always x^4. Are you trying to find a relation between the number on the left to the one on the right? If so, is that even needed. Just find the pattern of the left, find the pattern of the right and keep track of the two separately.