Решение задачи File 21

import random

def GenerateNumbers(fname):
    N = random.randint(1,11)
    print("N = ",N)
    L = []
    x = random.randint(1,4)
    L.append(x)
    for i in range(1,N):
        lst_rnd = list(range(1,5))
        lst_rnd.remove(x)
        x = random.choice(lst_rnd)
        L.append(x)    
    print(L)
    try:
        f = open(fname, "w")
        try:
            for x in L:
                line = str(x)+"\n"
                f.write(line)
        finally:
            f.close()
    except IOError:
        print('Write error: ',fname)

def EmptyFile(fname):
    open(fname, 'w').close()
    
def Write2File(fname,value):
    try:
        f = open(fname, "a")
        try:
            s = str(value)+'\n'
            f.write(s)
        finally:
            f.close()
    except IOError:
        print('Write error: ',fname)

f_input = "file21_input.txt"
#GenerateNumbers(f_input)

f_output = "file21_output.txt"
EmptyFile(f_output)

i = 0
flag = False
try:
    with open(f_input,'r') as f_in:
        for line in f_in:
            i += 1
            x = int(line.strip())
            print(x)    
            if i == 1:
                x1 = x
                l_max = x1
                l_max_line = 1
            elif i == 2:
                x2 = x
                if x1 > x2:
                    print("Local maximum:",l_max,"; Max line:",l_max_line)
                    Write2File(f_output,l_max_line)
                else:
                    l_max = x2
                    l_max_line = 2
            elif i == 3:
                x3 = x
                if x3 > x2:
                    l_max = x3
                    l_max_line = 3
                elif x1 < x2 and x2 > x3:
                    l_max = x2
                    print("Local maximum:",l_max,"; Max line:",l_max_line)
                    Write2File(f_output,l_max_line)
            else:
                x1 = x2
                x2 = x3
                x3 = x
                if x3 > x2:
                    l_max = x3
                    l_max_line = i
                elif x1 < x2 and x2 > x3:
                    print("Local maximum:",l_max,"; Max line:",l_max_line)
                    Write2File(f_output,l_max_line)

except IOError:
    print('Open error: ',f_source)
    
if i == 1:
    print("Local maximum:",l_max,"; Max line:",l_max_line)
    Write2File(f_output,l_max_line)
elif i == 2:
    if x1 < x2:
        print("Local maximum:",l_max,"; Max line:",l_max_line)
        Write2File(f_output,l_max_line)
else:
    if x2 < x3:
        print("Local maximum:",l_max,"; Max line:",l_max_line)
        Write2File(f_output,l_max_line)
									

program File21;
var
 S:String;
 F_in: File of Real;
 F_out: File of Integer;
 El2,El1,El:Real;
 i:integer;
begin
  Write('File: ');
  Readln(S);
  Assign(F_in,S);
  Reset(F_in);
  Write('File_out: ');
  Readln(S);
  Assign(F_out,S);
  ReWrite(F_out);
  Read(F_in,El1);
  Read(F_in,El);
  El2:=El1;
  I:=1;
  if (El1>El) then Write(F_out,i);
  while (not eof(F_in)) do
   begin
    El2:=El1;
    El1:=El;
    Read(F_in,El);
    inc(i);
    if (El<El1) and (El1>El2) then Write(F_out,i);
   end;
  if El1<El then Write(F_out,i+1);
  Close(F_in);
end.