PROGRAM MYPROG
    REAL A,B
    INTEGER N
    REAL Y(20)
    REAL X(20)
    REAL STEP
    INTEGER iH

    
    WRITE(*,*) 'Desired interval, seperated by whitespace: '
    READ(*,*) A, B
    WRITE(*,*) 'Desired number of samples(min 2,max 20): '
    READ(*,*) N
    IF(N.GT.20.OR.N.LT.2) THEN
    WRITE(*,*) 'Too many samples, try again'
    READ(*,*)
    STOP
    END IF
    WRITE(*,*) 'OK, ',N,'Samples on interval [',A, ',',B,']'
    WRITE(*,*) '---Calculating function x*x*sin(pi*x) for all samples---'
    STEP=(B-A)/(N-1)
    iH=1

    OPEN(11, FILE='output.dat', STATUS='unknown')

    DO i=1,N,1
       X(i)=A+(i-1)*STEP
       Y(i)=(X(i)*X(i)*sin(X(i)*2*ACOS(0.0)))!3.1415926535897932))
       WRITE(*,*) X(i),' has the corresponding value ', Y(i)
       IF(Y(i).GT.Y(iH)) THEN
       iH=i
       ENDIF

       WRITE(11,*) X(i),Y(i)
    ENDDO
   ! CALL SYSTEM('gnuplot -e plot "in.dat" -p')
    WRITE(*,*) 'The highest value was ', Y(iH),' occurring at x=',X(iH)
    
    CLOSE(11)

  END PROGRAM