很匆忙地写了一下，练练手感，可能有不少错的……
program gjdall;
uses math;
Const
maxlen=1500;
numbers=['0'..'9'];
Type
gjd=record
d:array[0..maxlen] of longint;
len:longint;
zf:boolean;
end;
Var
a,b:gjd;
Procedure print(p:gjd);forward;
Procedure initgjd(var p:gjd;k:longint);//初始化gjd置为k
var
i:longint;
s:string;
begin
str(abs(k),s);
p.len:=length(s);
fillchar(p.d,sizeof(p.d),0);
if k>=0 then p.zf:=true else p.zf:=false;
for i:=1 to length(s) do
p.d[i]:=ord(s[length(s)-i+1])-ord('0');
end;
Function initgjd(var p:gjd):gjd;//无参数默认为0
begin
initgjd(p,0);
exit(p);
end;
Function zero(P:gjd):boolean;//判断是否为0
begin
if (p.len=1) and (p.d[1]=0) then exit(true);
exit(false);
end;
Function big(p1,p2:gjd):boolean;//比较p1,p2绝对值大小
var
i:longint;
begin
if p1.len>p2.len then exit(true);
if p1.len<p2.len then exit(false);
for i:=p1.len downto 1 do
begin
if p1.d[i]>p2.d[i] then exit(true);
if p1.d[i]<p2.d[i] then exit(false);
end;
exit(false);
end;
Function equal(p1,p2:gjd):boolean;//判断绝对值是否相等
begin
if not big(p1,p2) and not big(p2,p1) then exit(true) else exit(false);
end;
Function Create(P:longint):gjd;//得到1eP
begin
initgjd(create);
create.len:=p;
create.d[p]:=1;
end;
Function realminus(p1,p2:gjd):gjd;//绝对值减
var
y,ans:gjd;
jw,i:longint;
flag:boolean;
begin
if equal(p1,p2) then exit(initgjd(realminus));
if big(p2,p1) then
begin
y:=p2;
p2:=p1;
p1:=y;
flag:=true;
end else flag:=false;
jw:=0;
initgjd(ans);
ans.len:=p1.len;
for i:=1 to ans.len do
begin
ans.d[i]:=p1.d[i]-p2.d[i]-jw;
if ans.d[i]<0 then
begin
inc(ans.d[i],10);
jw:=1;
end else jw:=0;
end;
while (ans.len>0) and (ans.d[ans.len]=0) do dec(ans.len);
if flag then ans.zf:=not ans.zf;
exit(ans);
end;
Function realadd(p1,p2:gjd):gjd;//绝对值加
var
ans:gjd;
i,jw:longint;
begin
initgjd(ans);
ans.len:=max(p1.len,p2.len);
jw:=0;
for i:=1 to ans.len do
begin
ans.d[i]:=p1.d[i]+p2.d[i]+jw;
jw:=ans.d[i] div 10;
ans.d[i]:=ans.d[i] mod 10;
end;
if jw>0 then begin inc(ans.len);ans.d[ans.len]:=jw;end;
while (ans.len>0) and (ans.d[ans.len]=0) do dec(ans.len);
exit(ans);
end;
Function RealCheng(p1,p2:gjd):gjd;//绝对值乘
var
i,j:longint;
ans:gjd;
begin
initgjd(ans);
ans.len:=p1.len+p2.len;
for i:=1 to p1.len do
for j:=1 to p2.len do
inc(ans.d[i+j-1],p1.d[i]*p2.d[j]);
for i:=1 to ans.len do
begin
inc(ans.d[i+1],ans.d[i] div 10);
ans.d[i]:=ans.d[i] mod 10;
end;
while (ans.len>0) and (ans.d[ans.len]=0) do dec(ans.len);
exit(ans);
end;
Function Add(p1,p2:gjd):gjd;//整数加
begin
if zero(p1) then exit(p2);
if zero(p2) then exit(p1);
if p1.zf and p2.zf then
exit(realadd(p1,p2));
if p1.zf and not p2.zf then
exit(realminus(p1,p2));
if not p1.zf and p2.zf then
exit(realminus(p2,p1));
add:=realadd(p1,p2);
add.zf:=not add.zf;
end;
Function minus(p1,p2:gjd):gjd;//整数减
begin
if zero(p1) then begin minus:=p2;minus.zf:=not minus.zf;exit;end;
if zero(p2) then exit(p1);
if p1.zf and p2.zf then exit(realminus(p1,p2));
if p1.zf and not p2.zf then exit(realadd(p1,p2));
if not p1.zf and p2.zf then
begin
minus:=realadd(p1,p2);
minus.zf:=not minus.zf;
exit;
end;
exit(realminus(p2,p1));
end;
Function cheng(p1,p2:gjd):gjd;//整数乘
begin
if zero(p1) or zero(p2) then begin initgjd(cheng);exit;end;
Cheng:=RealCheng(p1,p2);
if p1.zf xor p2.zf then cheng.zf:=false else cheng.zf:=true;
end;
Function divide(p:gjd;k:longint):gjd;//高精度整除整数
var
jw,i:longint;
ans:gjd;
flag:boolean;
begin
if zero(p) then exit(p);
jw:=0;
initgjd(ans);
ans.len:=p.len;
if k<0 then begin k:=-k;flag:=true; end else flag:=false;
for i:=p.len downto 1 do
begin
jw:=jw*10;
ans.d[i]:=(p.d[i]+jw) div k;
jw:=(p.d[i]+jw)- ans.d[i]*k;
end;
while (ans.len>0) and (ans.d[ans.len]=0) do dec(ans.len);
if flag then ans.zf:=not ans.zf;
exit(ans);
end;
Function divide(p1,p2:gjd):gjd;//高精度整除高精度
var
one,minusone,low,high,mid:gjd;
i:longint;
begin
if zero(p1) then exit(p1);
if zero(p2) then exit;
initgjd(one,1);
initgjd(minusone,-1);
if equal(p1,p2) then
if p1.zf xor p2.zf then exit(minusone) else
exit(one);
if big(p2,p1) then exit(initgjd(divide));
low:=create(max(p1.len-p2.len-2,1));
high:=create(max(p1.len-p2.len+2,1));
while big(high,low) do
begin
mid:=divide(add(low,high),2);
if equal(realcheng(p2,mid),p1) then begin low:=mid;break;end;
if big(p1,realcheng(p2,mid)) then low:=add(mid,one) else high:=minus(mid,one);
end;
while Big( realcheng(p2,low),p1) do low:=minus(low,one);
if p1.zf xor p2.zf then low.zf:=false else low.zf:=true;
exit(low);
end;
Function Sqr(P:gjd):gjd;
begin
exit(cheng(p,p));
end;
Function Sqrt(p:gjd):gjd;
var
low,high,one,mid:gjd;
begin
if not p.zf then exit;
if zero(p) then exit(p);
initgjd(low,1);
high:=p;
initgjd(one,1);
while big(high,low) do
begin
mid:=divide(add(low,high),2);
{write('low=');print(low);writeln;write('high=');print(high);writeln;
write('mid=');print(mid);writeln;}
if equal(sqr(mid),p) then exit(mid);
if big(p,sqr(mid)) then low:=Add(mid,one) else high:=minus(mid,one);
end;
//writeln('d');
while Big(sqr(low),p) do low:=minus(low,one);
exit(low);
end;
Function times(p:gjd;k:longint):gjd;//快速幂
begin
if k=1 then exit(p);
if k=0 then exit(initgjd(times));
if k mod 2=0 then exit(sqr(times(p,k div 2))) else exit(Cheng(sqr(times(p,k div 2)),p));
end;
Procedure readgjd(var p:gjd);//读入一行高精度
var
tmp:gjd;
i:longint;
c:char;
begin
initgjd(tmp);
tmp.len:=0;
while not eoln do
begin
read(c);
if c='-' then tmp.zf:=not tmp.zf;
if c in numbers then
begin
inc(tmp.len);
tmp.d[tmp.len]:=ord(c)-ord('0');
end;
end;
readln;
p:=tmp;
for i:=1 to p.len do
p.d[i]:=tmp.d[p.len-i+1];
end;
Procedure print(p:gjd);//输出一行高精度
var
i:longint;
begin
if not p.zf then write('-');
for i:=p.len downto 1 do
write(p.d[i]);
end;
begin
readgjd(a);
readgjd(b);
print(Add(a,b));writeln;
print(minus(a,b));writeln;
print(cheng(a,b));
writeln;
print(divide(a,b));writeln;
print(sqr(a));
writeln;
print(sqr(b));
writeln;
print(sqrt(a));
writeln;
print(sqrt(b));
end.