<div dir="ltr"><span style="font-family:arial,sans-serif;font-size:12.800000190734863px">you should do :</span><div><span style="font-family:arial,sans-serif;font-size:12.800000190734863px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:12.800000190734863px">main = print $ center (1,2), (3, 4)</span><br>
</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Sat, May 10, 2014 at 1:51 PM, Roelof Wobben <span dir="ltr"><<a href="mailto:r.wobben@home.nl" target="_blank">r.wobben@home.nl</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Hello, <br>
<br>
I have to find the center of 2 points as a assigment for a course on
fpcomplete. This is no homework because I do a self-study. <br>
<br>
So I did this: <br>
<br>
center (x1,y1) (x2,y2) = ( ((x1+x2)/2),((y1+y2)/2) )<br>
main = print $ center ((1,2), (3, 4))<br>
<br>
but now I see this error message : <br>
<span></span>
<div>
<div style="display:block">Main.hs@2:8-2:13
<ul>
<li>
<div>
<div>No instance for (Show (((t0,
t1), (t2, t3)) -> ((t0, t1), (t2, t3)))) arising from
a use of `print'
Possible fix: add an instance declaration for (Show
(((t0, t1), (t2, t3)) -> ((t0, t1), (t2, t3))))
In the expression: print
In the expression: print $ center ((1, 2), (3, 4))
In an equation for `main': main = print $ center ((1,
2), (3, 4))</div><span class="HOEnZb"><font color="#888888">
</font></span></div><span class="HOEnZb"><font color="#888888">
</font></span></li><span class="HOEnZb"><font color="#888888">
</font></span></ul><span class="HOEnZb"><font color="#888888">
</font></span></div><span class="HOEnZb"><font color="#888888">
</font></span></div><span class="HOEnZb"><font color="#888888">
Roelof<br>
<br>
</font></span></div>
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<br></blockquote></div><br></div>