Conditional statement in c language

Parth786 · Jun 27, 2017

I had been reading about conditional statement (if, else or if else or if or if) and Now I want to use conditional statement in Program. Let’s suppose, four switches and one LED connected to microcontroller. I wrote some c programs with example but I am not sure whether its right or wrong. so if there is any mistake please let me know.

If press switch1, LED should be ON and If don’t press switch1, LED should be OFF
If press switch2, LED should be ON and If don’t press switch2, LED should be OFF
If press switch3, LED should be ON and If don’t press switch3, LED should be OFF
If press switch4, LED should be ON and If don’t press switch4, LED should be OFF

C program sing If and else condition

Code:

#include<REGX51.h>

#define LED_ON         (1)
#define LED_OFF        (0)

#define Switch1_ON     (1)
#define Switch2_ON     (1)
#define Switch3_ON     (1)
#define Switch4_ON     (1)

/*set bit to LED*/
sbit LED = P1^0;

/*set bits to Switch*/
sbit  Switch1 = P2^0;
sbit  Switch2 = P2^1;
sbit  Switch3 = P2^2;
sbit  Switch4 = P2^3;

void main()
{
    while (1)
    {
      if(Switch1 == Switch1_ON)
      {
        LED = LED_ON;   
      }

      else
      {  
        LED = LED_OFF;
      }
      if(Switch2 == Switch2_ON)
      {
        LED = LED_ON;   
      }

       else
      {  
        LED = LED_OFF;
      }
       if(Switch3 == Switch3_ON)
      {
        LED = LED_ON;   
      }

       else
      {  
        LED = LED_OFF;
      }
       if(Switch4 == Switch4_ON)
      {
        LED = LED_ON;   
      }

       else
      {  
        LED = LED_OFF;
      }
      }
   
}

C program with If and if else condition

Code:

#include<REGX51.h>

#define LED_ON         (1)
#define LED_OFF        (0)

#define Switch1_ON     (1)
#define Switch2_ON     (1)
#define Switch3_ON     (1)
#define Switch4_ON     (1)

#define Switch1_OFF    (0)
#define Switch2_OFF    (0)
#define Switch3_OFF    (0)
#define Switch4_OFF    (0)

/*set bit to LED*/
sbit LED = P1^0;

/*set bits to Switch*/
sbit  Switch1 = P2^0;
sbit  Switch2 = P2^1;
sbit  Switch3 = P2^2;
sbit  Switch4 = P2^3;

void main()
{
    while (1)
    {
      if(Switch1 == Switch1_ON)
      {
        LED = LED_ON;   
      }

        else if (Switch1 == Switch1_OFF)
      {  
        LED = LED_OFF;
      }
      if(Switch2 == Switch2_ON)
      {
        LED = LED_ON;   
      }

         else if (Switch2 == Switch2_OFF)
      {  
        LED = LED_OFF;
      }
       if(Switch3 == Switch3_ON)
      {
        LED = LED_ON;   
      }

         else if (Switch3 == Switch4_OFF)
      {  
        LED = LED_OFF;
      }
       if(Switch4 == Switch4_ON)
      {
        LED = LED_ON;   
      }

         else if (Switch4 == Switch4_OFF)
      {  
        LED = LED_OFF;
      }
    }   
}

If press switch1, LED should be ON
If press switch2, LED should be ON
If press switch3, LED should be ON
If press switch4, LED should be ON
If don’t press any switches, LED should be OFF

C programming using if if if and else conditions

Code:

#include<REGX51.h>

#define LED_ON         (1)
#define LED_OFF        (0)

#define Switch1_ON     (1)
#define Switch2_ON     (1)
#define Switch3_ON     (1)
#define Switch4_ON     (1)

/*set bit to LED*/
sbit LED = P1^0;

/*set bits to Switch*/
sbit  Switch1 = P2^0;
sbit  Switch2 = P2^1;
sbit  Switch3 = P2^2;
sbit  Switch4 = P2^3;

void main()
{
    while (1)
    {
      if(Switch1 == Switch1_ON)
        {
          LED = LED_ON;   
          if(Switch2 == Switch2_ON)
          {
            LED = LED_ON;   
            if(Switch3 == Switch3_ON)
             {
              LED = LED_ON;   
              if(Switch4 == Switch4_ON)
               {
                 LED = LED_ON;   
               }
             }
           }
        }
                 
            else
      {  
        LED = LED_OFF;
      }
    }      
}

I think my last program is not in correct way. if you find anywhere wrong please let me know

WBahn · Jun 27, 2017

Parth786 said:
I had been reading about conditional statement (if, else or if else or if or if) and Now I want to use conditional statement in Program. Let’s suppose, four switches and one LED connected to microcontroller. I wrote some c programs with example but I am not sure whether its right or wrong. so if there is any mistake please let me know.

Well, vead, does it do what you wanted it to do? If not, then it is wrong. If so, then there is at least a chance that it is right. So which is it?

Parth786 · Jun 27, 2017

WBahn said:
does it do what you wanted it to do? If not, then it is wrong. If so, then there is at least a chance that it is right. So which is it?

Well, vead,

as per as my knowledge. I have written correct program. first and second program will do job but I had doubt in last but I am sure there will be little mistake in closing brackets

eetech00 · Jun 27, 2017

Hi

Which micro controller and C compiler are you using?

WBahn · Jun 27, 2017

Parth786 said:
as per as my knowledge. I have written correct program. first and second program will do job but I had doubt in last but I am sure there will be little mistake in closing brackets

Have you even tried to compile them?

Have you tried to run them?

Have you checked to see if they do what you want them to do?

Parth786 · Jun 27, 2017

WBahn said:
Have you even tried to compile them?

Have you tried to run them?

Have you checked to see if they do what you want them to do?

Yes I have compiled code without error
Yes I tried to run them but its not working. to see why its not working i connect only one switch and LED and wrote program but its not working according my program. I wanted to LED ON when switch is high and OFF if switch is low. but its work opposite. LED is ON when switch is open and LED OFF when switch is closed. Now I am in on the way. I will post that Program.

Ramussons · Jun 28, 2017

This are your conditions:

Parth786 said:
If press switch1, LED should be ON and If don’t press switch1, LED should be OFF
If press switch2, LED should be ON and If don’t press switch2, LED should be OFF
If press switch3, LED should be ON and If don’t press switch3, LED should be OFF
If press switch4, LED should be ON and If don’t press switch4, LED should be OFF

Now, each of these conditions are Independent of each other. Condition of any Switch x, in no way, affects the other switches.

So, you cannot have a "IF ELSE" condition. If you put an ELSE condition, then in case Switch 1 is ON, that LED will light up and the prog will exit.

You will need to have 4 standalone IF statements.

Parth786 · Jun 28, 2017

Ramussons said:
This are your conditions:

Now, each of these conditions are Independent of each other. Condition of any Switch x, in no way, affects the other switches.

So, you cannot have a "IF ELSE" condition. If you put an ELSE condition, then in case Switch 1 is ON, that LED will light up and the prog will exit.

You will need to have 4 standalone IF statements.

Actually I am trying to simulate on Proteus design since last 2 hours but its not giving proper output. I don't understand why does LED automatically turn ON. I tried with different different approach but I am not getting result which I want to get. Now I stuck weather my hardware design is wrong or my program is wrong. I am sure my program is correct I think there problem in hardware design
first problem is that LED Turn on Automatically so I tried to OFF initially. and checked with below program. but still LED is on

Code:

#include<REGX51.h>

#define LED_ON         (1)
#define LED_OFF        (0)

/*set bit P1^0 to LED*/
sbit LED = P1^0;

void main()
{
       LED = LED_OFF;
     
}

just to rectify I tried below program but this also not working. I am not getting what's the exactly problem are?

Code:

#include<REGX51.h>

#define LED_ON         (1)
#define LED_OFF        (0)
#define Switch1_ON     (1)
#define Switch1_OFF    (0)


/*set bit P1^0 to LED*/
sbit LED = P1^0;

/*set bit P2^0 to Switch*/
sbit  Switch1 = P2^0;


void main()
{

    while (1)
    {
       
      if(Switch1 == Switch1_ON )
      {
               LED = LED_ON; 
      }

     else
     {       LED = LED_OFF; 
  
     }
  }

   
}

any how I am trying to get result if something is happen I will tell you

Ramussons · Jun 29, 2017

Parth786 said:
I had been reading about conditional statement (if, else or if else or if or if) and Now I want to use conditional statement in Program. Let’s suppose, four switches and one LED connected to microcontroller. I wrote some c programs with example but I am not sure whether its right or wrong. so if there is any mistake please let me know.

Sorry, did'nt notice this.
If this is the condition, then logically. the condition would be IF .OR.
If Switch 1 is Pressed OR Switch 2 is Pressed OR switch 3 is Pressed OR Switch 4 is Pressed, LED should be ON.
Why is a IF ELSE condition being invoked?

Or, maybe, I did not get your question

Thread starter	Similar threads	Forum	Replies	Date
K	[SOLVED]Conditional Pre-processor	Programming & Languages	15	Jan 7, 2023
F	LTspice: using conditional statements to switch ON & OFF voltage–controlled switches in a resonance circuit	Homework Help	2	Dec 17, 2022
F	How to apply the the conditional probability and chain rule formulas in a multivariable case?	General Science, Physics & Math	0	Jun 27, 2022
D	How to control a servo motor for example with a conditional statement on arduino	Programming & Languages	13	Jun 20, 2022
	Hardware design for conditional operation	Digital Design	0	Apr 23, 2022

Conditional statement in c language

Join our Engineering Community! Sign-in with:

Conditional statement in c language

Parth786

WBahn

Parth786

eetech00

WBahn

Parth786

Ramussons

Parth786

Ramussons

You May Also Like

ST’s Packs MPU-Level Performance in New 600 MHz Bootflash MCUs

4 Fiber Optic Networking Spotlights From the Optical Fiber Conference

Microchip’s Portfolio of Integrated Motor Drivers Grows With New Family

Microchip Expands Its Serial SRAM Devices to 2 Mb and 4 Mb