conditional statement in C++

Write a program that will accept a mark and assign letter grade according to

the following table.

Grade Mark

A > = 90

B > = 80 but < 90

C > = 70 but < 80

D > = 60 but < 70

F < 60

PROGRAM:

#include <iostream.h>

#include <conio.h>

void main() {

clrscr();

int mark, grade;

cout<<"Enter your mark: ";

cin>>mark;

if(mark>=90)

cout<<"\nYour grade is A";

else if(mark>=80 && mark<90)

cout<<"\nyour grade is B";

else if(mark>=70 && mark<80)

cout<<"\nyour grade is C";

else if(mark>=60 && mark<70)

cout<<"\nyour grade is D";

else

cout<<"\nyour grade is F";

getch();

}//end of the program