Chương trình 17

PROGRAM so_pi;
VAR SoPi: REAL;
i, dau: INTEGER;
n: LONGINT;
BEGIN
write('Hay cho so cac so hang de tinh so Pi :');
readln(n); {so cac so hang cua tong}
IF n>0 THEN
BEGIN
soPi:=0;
dau:=1;
FOR i:= 0 TO n DO
BEGIN soPi:= soPi + dau*1/(2*i + 1);
dau:= -dau END;
writeln('So Pi gan bang ', soPi*4);
END {khong co dau ; vi dung truoc else}
ELSE
BEGIN
writeln('So ban nhap phai > 0');
writeln('Nhan phim Enter va chay lai chuong trinh');
END;
readln
END.

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