I'm at my wits end. Everywhere I look I end up finding nothing.

I'm making a program in the Free Pascal IDE that calculates the mean, medium, and mode of 20 numbers. I managed to make something but it keeps on crashing and giving me erros. Can someone help? ~~~~~~~~~~~~~~~

uses wincrt; type larik=array [1..100] of integer; var a:larik; i,j,n:integer; Procedure input; begin write('Input Data : ');readln(n); for i:=1 to n do readln(a[i]); end; Function mean:real; var x:real; begin x:=0; for i:=1 to n do begin x:=x+a[i]; end; mean:=x/n; end; Function median:real; var b:integer; begin for i:=1 to n-1 do begin b:=0; for j:=n downto i do if a[j]0 then modus:=i; end; end; begin input; mean; median; modus; writeln('Mean : ',mean:3:2); writeln('Median : ',median:2:1); writeln('Modus : ',a[modus]); end.

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