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[SOLVED] "Invalid Expression" problem

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shivammun13

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hello, i have been working on a code for a program which displays the number of counts on an LCD display. When count = 0 it should display Parking Full. When i compiled the code it says invalid expression. I used conversion to string before that but it did not work, so i wrote my code without string conversions.
Can anyone check and suggest why it is not compiling? Here my full code:

Code: 
sbit GreenLED at RD6_bit;
sbit RedLED at RD7_bit;
sbit IncrementButton at RB1_bit;
sbit DecrementButton at RB0_bit;
sbit LCD_EN at RD0_bit;
sbit LCD_RS at RD1_bit;
sbit LCD_D4 at RD2_bit;
sbit LCD_D5 at RD3_bit;
sbit LCD_D6 at RD4_bit;
sbit LCD_D7 at RD5_bit;

sbit GreenLED_Direction at TRISD6_bit;
sbit RedLED_Direction at TRISD7_bit;
sbit IncrementButton_Direction at TRISB1_bit;
sbit DecrementButton_Direction at TRISB0_bit;
sbit LCD_RS_Direction at TRISD0_bit;
sbit LCD_EN_Direction at TRISD1_bit;
sbit LCD_D4_Direction at TRISD2_bit;
sbit LCD_D5_Direction at TRISD3_bit;
sbit LCD_D6_Direction at TRISD4_bit;
sbit LCD_D7_Direction at TRISD5_bit;

int count = 10;
const int MAX_COUNT = 10;

void main() {

GreenLED_Direction = 0;
RedLED_Direction = 0;
IncrementButton_Direction = 1;
DecrementButton_Direction = 1;

Lcd_Init();
Lcd_Cmd(_LCD_CLEAR);
Lcd_Cmd(_LCD_CURSOR_OFF);
Lcd_Out(1, 1, "P.SLOT LEFT:");
Lcd_Out(1, 13, "10");

while(1) {

 if (!DecrementButton) {
    count = count-1;

    if(count < 0){
       count = 0;
       }
       if (count == 0) {
        GreenLED = 0;
        RedLED = 1;
        } else {
        GreenLED = 1;
        RedLED = 0;
        }
        while (!DecrementButton);
    }

 if (!IncrementButton) {
     count=count+1;

     if (count > MAX_COUNT) {
        count = MAX_COUNT;
      }
      if (count > 0){
      GreenLED = 1;
      RedLED = 0;
      } else{
      GreenLED = 0;
      RedLED = 1;
      }
      while (!IncrementButton);
    }

    if (count == 10) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "10");
    }
    if (count == 9) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "9");
    }
    if (count == 8) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "8");
    }
    if (count == 7) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "7");
    }
    if (count == 6) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "6");
    }
    if (count == 5) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "5");
    }
    if (count == 4) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "4");
    }
    if (count == 3) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "3");
    }
    if (count == 2) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "2");
    }
    if (count == 1) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "1");
    }
    if (count == 0) {
    Lcd_Out(1, 13, "  ");
    Lcd_Out(1, 13, "0");
    Lcd_Out(2, 3, "PARKING FULL");
    }
 }
 
Last edited by a moderator:

Solution
betwixt
You are missing the closing bracket (from main). If you change the formatting so each bracketed expression or function is indented it look like this:
Code: 
sbit GreenLED at RD6_bit;
sbit RedLED at RD7_bit;
sbit IncrementButton at RB1_bit;
sbit DecrementButton at RB0_bit;
sbit LCD_EN at RD0_bit;
sbit LCD_RS at RD1_bit;
sbit LCD_D4 at RD2_bit;
sbit LCD_D5 at RD3_bit;
sbit LCD_D6 at RD4_bit;
sbit LCD_D7 at RD5_bit;

sbit GreenLED_Direction at TRISD6_bit;
sbit RedLED_Direction at TRISD7_bit;
sbit IncrementButton_Direction at TRISB1_bit;
sbit DecrementButton_Direction at TRISB0_bit;
sbit LCD_RS_Direction at TRISD0_bit;
sbit LCD_EN_Direction at TRISD1_bit;
sbit LCD_D4_Direction at TRISD2_bit;
sbit LCD_D5_Direction at TRISD3_bit;
sbit...
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You are missing the closing bracket (from main). If you change the formatting so each bracketed expression or function is indented it look like this:
Code: 
sbit GreenLED at RD6_bit;
sbit RedLED at RD7_bit;
sbit IncrementButton at RB1_bit;
sbit DecrementButton at RB0_bit;
sbit LCD_EN at RD0_bit;
sbit LCD_RS at RD1_bit;
sbit LCD_D4 at RD2_bit;
sbit LCD_D5 at RD3_bit;
sbit LCD_D6 at RD4_bit;
sbit LCD_D7 at RD5_bit;

sbit GreenLED_Direction at TRISD6_bit;
sbit RedLED_Direction at TRISD7_bit;
sbit IncrementButton_Direction at TRISB1_bit;
sbit DecrementButton_Direction at TRISB0_bit;
sbit LCD_RS_Direction at TRISD0_bit;
sbit LCD_EN_Direction at TRISD1_bit;
sbit LCD_D4_Direction at TRISD2_bit;
sbit LCD_D5_Direction at TRISD3_bit;
sbit LCD_D6_Direction at TRISD4_bit;
sbit LCD_D7_Direction at TRISD5_bit;

int count = 10;
const int MAX_COUNT = 10;

void main() 
{

  GreenLED_Direction = 0;
  RedLED_Direction = 0;
  IncrementButton_Direction = 1;
  DecrementButton_Direction = 1;

  Lcd_Init();
  Lcd_Cmd(_LCD_CLEAR);
  Lcd_Cmd(_LCD_CURSOR_OFF);
  Lcd_Out(1, 1, "P.SLOT LEFT:");
  Lcd_Out(1, 13, "10");

  while(1) 
  {
    if (!DecrementButton) 
    {
      count = count-1;
      if(count < 0)
      {
        count = 0;
      }
      if (count == 0) 
      {
        GreenLED = 0;
        RedLED = 1;
      } 
      else 
      {
        GreenLED = 1;
        RedLED = 0;
      }
      
      while (!DecrementButton);
    }

    if (!IncrementButton) 
    {
      count=count+1;
      if (count > MAX_COUNT) 
      {
          count = MAX_COUNT;
      }
      if (count > 0)
      {
          GreenLED = 1;
          RedLED = 0;
        }
        else
        {
          GreenLED = 0;
          RedLED = 1;
        }
      
        while (!IncrementButton);
      }

      if (count == 10) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "10");
      }
      if (count == 9) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "9");
      }
      if (count == 8) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "8");
      }
      if (count == 7) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "7");
      }
      if (count == 6) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "6");
      }
      if (count == 5) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "5");
      }
      if (count == 4) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "4");
      }
      if (count == 3) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "3");
      }
      if (count == 2) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "2");
      }
      if (count == 1) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "1");
      }
      if (count == 0) 
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "0");
        Lcd_Out(2, 3, "PARKING FULL");
      }
  }

and you can see your closing bracket matches the while statement instead of main.
Very messy and over complicated display routine.

Brian.
 

Upvote 1 Downvote
Solution
betwixt said:
You are missing the closing bracket (from main). If you change the formatting so each bracketed expression or function is indented it look like this:
Code: 
sbit GreenLED at RD6_bit;
sbit RedLED at RD7_bit;
sbit IncrementButton at RB1_bit;
sbit DecrementButton at RB0_bit;
sbit LCD_EN at RD0_bit;
sbit LCD_RS at RD1_bit;
sbit LCD_D4 at RD2_bit;
sbit LCD_D5 at RD3_bit;
sbit LCD_D6 at RD4_bit;
sbit LCD_D7 at RD5_bit;

sbit GreenLED_Direction at TRISD6_bit;
sbit RedLED_Direction at TRISD7_bit;
sbit IncrementButton_Direction at TRISB1_bit;
sbit DecrementButton_Direction at TRISB0_bit;
sbit LCD_RS_Direction at TRISD0_bit;
sbit LCD_EN_Direction at TRISD1_bit;
sbit LCD_D4_Direction at TRISD2_bit;
sbit LCD_D5_Direction at TRISD3_bit;
sbit LCD_D6_Direction at TRISD4_bit;
sbit LCD_D7_Direction at TRISD5_bit;

int count = 10;
const int MAX_COUNT = 10;

void main()
{

  GreenLED_Direction = 0;
  RedLED_Direction = 0;
  IncrementButton_Direction = 1;
  DecrementButton_Direction = 1;

  Lcd_Init();
  Lcd_Cmd(_LCD_CLEAR);
  Lcd_Cmd(_LCD_CURSOR_OFF);
  Lcd_Out(1, 1, "P.SLOT LEFT:");
  Lcd_Out(1, 13, "10");

  while(1)
  {
    if (!DecrementButton)
    {
      count = count-1;
      if(count < 0)
      {
        count = 0;
      }
      if (count == 0)
      {
        GreenLED = 0;
        RedLED = 1;
      }
      else
      {
        GreenLED = 1;
        RedLED = 0;
      }
     
      while (!DecrementButton);
    }

    if (!IncrementButton)
    {
      count=count+1;
      if (count > MAX_COUNT)
      {
          count = MAX_COUNT;
      }
      if (count > 0)
      {
          GreenLED = 1;
          RedLED = 0;
        }
        else
        {
          GreenLED = 0;
          RedLED = 1;
        }
     
        while (!IncrementButton);
      }

      if (count == 10)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "10");
      }
      if (count == 9)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "9");
      }
      if (count == 8)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "8");
      }
      if (count == 7)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "7");
      }
      if (count == 6)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "6");
      }
      if (count == 5)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "5");
      }
      if (count == 4)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "4");
      }
      if (count == 3)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "3");
      }
      if (count == 2)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "2");
      }
      if (count == 1)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "1");
      }
      if (count == 0)
      {
        Lcd_Out(1, 13, "  ");
        Lcd_Out(1, 13, "0");
        Lcd_Out(2, 3, "PARKING FULL");
      }
  }

and you can see your closing bracket matches the while statement instead of main.
Very messy and over complicated display routine.

Brian.
Click to expand...
Thanks man! Actually i started using conversions to convert the counts to strings but i was having a lot of problems and the lcd was not displaying the counting. As a result i tried doing it this way. I don't know if this will work. I just hope it displays the counting sequence🙂
 

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