Dùng ngôn ngữ Pascal để viết các chương trình tính tổng sau (n là số tự nhiên được nhập từ bàn phím )
A) s=1+2+3+…+n
B) s = 2+4+6+…+n (n số chẵn)
C) s = 1+3+5+…+n (n số lẻ)
D) s= 1/2+ 1/4+ 1/6+…+1/n (n số chẵn)
E) s = 1+ 1/3+ 1/5+ 1/7+…+1/n (n số lẻ)
F) s= 1/3+ 1/6+ 1/9+…+1/n
A)
#include <bits/stdc++.h>
using namespace std;
int main(){
int n,tong=0;
cin>>n;
for(int i=1;i<=n;i++){
tong+=i;
}
cout<<tong;
//samon247
return 0;
}
B)
#include <bits/stdc++.h>
using namespace std;
#define cls system(“cls”)
int main(){
int n,tong=0;
cin>>n;
if(n%2!=0){
cls;
return main();
}
for(int i=2;i<=n;i+=2){
tong+=i;
}
cout<<tong;
//samon247
return 0;
}
C)
#include <bits/stdc++.h>
using namespace std;
#define cls system(“cls”)
int main(){
int n,tong=0;
cin>>n;
if(n%2==0){
cls;
return main();
}
for(int i=1;i<=n;i+=2){
tong+=i;
}
cout<<tong;
//samon247
return 0;
}
D)
#include <bits/stdc++.h>
using namespace std;
#define cls system(“cls”)
int main(){
int n;
float tong=0;
cin>>n;
if(n%2!=0){
cls;
return main();
}
for(int i=2;i<=n;i+=2){
tong+=(float)1/i;
}
cout<<tong;
//samon247
return 0;
}
E)
#include <bits/stdc++.h>
using namespace std;
#define cls system(“cls”)
int main(){
int n;
float tong=0;
cin>>n;
if(n%2==0){
cls;
return main();
}
for(int i=1;i<=n;i+=2){
tong+=(float)1/i;
}
cout<<tong;
//samon247
return 0;
}
F)
#include <bits/stdc++.h>
using namespace std;
#define cls system(“cls”)
int main(){
int n;
float tong=0;
cin>>n;
if(n%3!=0){
cls;
return main();
}
for(int i=1;i<=n;i+=3){
tong+=(float)1/i;
}
cout<<tong;
//samon247
return 0;
}
A)
program ct;
uses crt;
var S,i,n:integer;
begin
clrscr;
write(‘nhap n:=’);readln(n);
S:=0;
for i:=1 to n do S:=S+i;
writeln(‘tong la:’,S);
readln
end.
B)
program ct;
uses crt;
var S,i,n:integer;
begin
clrscr;
write(‘nhap n:=’);readln(n);
S:=0;
for i:=1 to n do
if i mod 2=0 then S:=S+i;
writeln(‘tong la:’,S);
readln
end.
C)
program ct;
uses crt;
var S,i,n:integer;
begin
clrscr;
write(‘nhap n:=’);readln(n);
S:=0;
for i:=1 to n do
if i mod 2=1 then S:=S+i;
writeln(‘tong la:’,S);
readln
end.
D)
program ct;
uses crt;
var i,n:integer;S:real;
begin
clrscr;
write(‘nhap n:=’);readln(n);
S:=0;
for i:=1 to n do
if i mod 2=0 then S:=S+1/i;
writeln(‘tong cac so chan la:’,S);
readln
end.
E)
program ct;
uses crt;
var i,n:integer;S:real;
begin
clrscr;
write(‘nhap n:=’);readln(n);
S:=0;
for i:=1 to n do
if i mod 2=1 then S:=S+1/i;
writeln(‘tong cac so lela:’,S);
readln
end.
F)
program ct;
uses crt;
var i,n:integer; S:real;
begin
write(‘nhap n:=’);readln(n);
S:=0; i:=3;
while i<=n do
begin
S:=S+1/i;
i:=i+3;
end;
writeln(‘tong la:’,S);
readln
end.