Thread: sqrt() question...

Ok, so im still pretty new to C programming and i was reading the stickies and i found a post in the C Book Recomendations sticky that has some assignments. The assignment was to print out the square root of the numbers of 1-10. It sounded pretty simple and so i decided to do it. I came up with this:

Code:

#include <stdio.h>
#include <math.h>
int main()
{
        int i=1;
        int square = 0;
        while(i <= 10){
                square = sqrt(i);
                printf("%d\n", &square);
                i++;
                }
}

The first problem i came across was the compiler spitting out some wierd warning at me, but i found out that there was a special flag that i had to use to link the math.h library.

Code:

gcc -o newsqrt newsqrtc -lm

which i assume means ''Link Math'' (please correct me if im wrong i couldnt find it in the documentation that i found). So i run the program and it doesnt work like i thought it would.

Code:

Mike@laptop:~> ./newsqrt
-1078179784
-1078179784
-1078179784
-1078179784
-1078179784
-1078179784
-1078179784
-1078179784
-1078179784
-1078179784

I assume that its memory addresses or something.
i recompiled the proggram using

Code:

gcc -o -ggdb newsqrt newsqrt.c

and i run it through gdb and i get this:

Code:

(gdb) l
1       #include <stdio.h>
2       #include <math.h>
3       int main()
4       {
5               int i=1;
6               int square = 0;
7               while(i <= 10){
8                       square = sqrt(i);
9                       printf("%d\n", &square);
10                      i++;
(gdb) b 7
Breakpoint 1 at 0x8048433: file newsqrt.c, line 7.
(gdb) r
Starting program: /home/Mike/newsqrt

Breakpoint 1, main () at newsqrt.c:7
7               while(i <= 10){
(gdb) s
8                       square = sqrt(i);
(gdb) s
9                       printf("%d\n", &square);
(gdb) s
-1075492664
10                      i++;

and then it goes through it all again.
My big questions are; what am i forgetting and what (if anything) can i do to make this code better?
i hope that this isnt too much for my first thread. I searched the forum for people with a similar problem but i didnt find it.
thanks in advance for the help.
-Mikey_ickey

Originally Posted by maxorator

Use %g instead of %d in your printf() function, because %d means an integer.
Also, don't you think this would be easier:

Code:

#include <stdio.h>
#include <math.h>

int main(void){
    for(int i=1;i<=10;i++){
        printf("%g\n",sqrt(i));
    }
    return 0;
}

OH YEAH! I guess that would be easier. Thanks guys.