用函数调用来求（1!+2!+3!+......+20!)

Pascal 代码

program solve;

var
solve,a,b,i:longint;

function doit(x:longint):longint;
var j:longint;
begin
doit:=1;
for j:=1 to x do doit:=doit*j;
end;

begin
solve:=1;
for i:=1 to 20 do solve:=solve*doit(i);
writeln(solve);
end.

long fact(int n)
if (n==1|| n==0) return 1;
else return n*fact(n-1);
}
void main(){
long sum=0;
for (int i=1;i<=20;i++)
sum+=fact(i);
printf("%d\n",sum);
}