1 //加法过程
2 procedure plus(var a1,b1:arr;var x:arr);
3 var i,k:integer;
4 begin
5 k:=0;
6 for i:=1 to l do
7 begin
8 a1[i]:=a1[i]+b1[i]+k;
9 k:=a1[i] div 10;
10 a1[i]:=a1[i] mod 10;
11 end;
12 if k>0 then begin inc(l);a[l]:=k;end;
13 x:=a1;
14 end;
15
16 //加法函数
17 function plus(a,b:arr):arr;
18 var i,c:integer;
19 begin
20 c:=0;
21 for i:=1 to l do
22 begin
23 a[i]:=a[i]+b[i]+c;
24 c:=a[i] div 10;
25 a[i]:=a[i] mod 10;
26 end;
27 if c>0 then begin inc(l);a[l]:=c;end;
28 plus:=a;
29 end;
30 //减法过程
31 procedure minus(var a:numtype;var la:integer;b:numtype); {计算a=a-b,返回差a及其长度la}
32 var
33 i:integer;
34 begin
35 for i:=1 to la do {逐位相减}
36 begin
37 if a[i]<b[i] {借位}
38 then begin dec(a[i+1]);a[i] :=a[i]+10;end;
39 a[i] :=a[i]-b[i]; {计算差的第i位}
40 end;
41 while a[la]=0 do dec(la); {计算差的实际长度}
42 end;
