guidance with writing program

This is a discussion on guidance with writing program within the C Programming forums, part of the General Programming Boards category; Hi, I am trying to write my first c program for an assignment, so I'm not lookin for someone to ...

  1. #1
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    guidance with writing program

    Hi,

    I am trying to write my first c program for an assignment, so I'm not lookin for someone to write it for me I know that i'm missing some things or steps in the code, but can't work out what exactly. As far as I can tell, I have declared the constants and variables and assigned correct data types where necessary, but i'm not sure about the way I have set out the calculations and think this is where the problem could be. The program is supposed to give the value of several different resistors after the user inputs two variable values. Any guidance would be appreciated.


    Regards, phoenixg
    Attached Files Attached Files

  2. #2
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    Other than a mismatched comment marker (/* missing) it looks pretty good.

    Solving for a common emitter amplifier is pretty straight forward...

    Is there a specific problem?

    (As a matter of custom... please post your code in the open using [ code] [/code] tags in future.)

  3. #3
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    Code:
    	float R1, R2, R3, R4;
           ....
    	printf("Resistors:\n");
    	printf("R1 = %10d ohm\n", R1); 
    	printf("R2 = %10d ohm\n", R2);
    	printf("R3 = %10d ohm\n", R3);
    	printf("R4 = %10d ohm\n\n", R4);
    You should not print float variable with %d.
    Compiler cannot promote type for variadic arg function like printf,scanf,...
    If you have sin( 3 ). 3 is of course type int. But since compiler can see prototype of sin ( double sin(double); ) int 3 will be promoted to correct type.
    But for variadic arg function, no such thing can be performed.
    printf(3): formatted output conversion - Linux man page
    Last edited by Bayint Naung; 03-26-2011 at 06:27 AM.

  4. #4
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    r1 and r2 should be R1 and R2, surely.

  5. #5
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    Thanks for that, everyone. I looked at it hundred times and didn't see the r1 and
    r2.

    I only gave the output a int value because that is what the design said to do. I also thought that since i had given it a float value that it should stay that way.

    I still can't get it to compile though. It refers to an 'expected expression before )', in the error message when I compile it, but i still haven't worked out how to use the error messages to locate the problem.

    Regards, phoenixg

  6. #6
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    Quote Originally Posted by phoenixg View Post
    Thanks for that, everyone. I looked at it hundred times and didn't see the r1 and
    r2.

    I only gave the output a int value because that is what the design said to do. I also thought that since i had given it a float value that it should stay that way.

    I still can't get it to compile though. It refers to an 'expected expression before )', in the error message when I compile it, but i still haven't worked out how to use the error messages to locate the problem.

    Regards, phoenixg
    Code:
     
    #include <stdio.h>		  	  	  	  			/*printf, scanf definitions*/
    #include <math.h>
    
    
    #define Vc 3.3 
    #define	Ve 0.75	  	 	 	  	  	  	  	  /* definition of the constants */
    #define Vin 0.02
    #define Hfe 95
    
    int main(void)
    {
    
    	float Ic,Vcc;								/*declared variables*/
    	float R1, R2, R3, R4;
    	float Ib, Vb, Ks, Vout;
                                                        V---- Missing comment prefix
    	printf("Enter the value of Ic:");	/*	prompts for the variables from the user*/
    	scanf("%f", &Ic);	   	   	   	   	   		/*inputs the variable as a float*/
    	
    	printf("Enter the value of Vcc:");
    	scanf("%f", &Vcc);
    	
    	printf("===================");
    	
      	Ib = Ic / Hfe;	   	   	   	   	      	    /*calculates the base current*/
    	R1 = (Vcc - Vc) / Ic;	    				/*calculates the value of R1*/
    	R2 = Ve / (Ic + Ib);						/*calculates the value of R2*/
    	Vb = Ve + 0.7;	    						/*calculates the value of Vb*/
    	R4 = Vb / (5 * Ib);	    					/*calculates the value of R4*/
    	R3 = (Vcc - Vb) / (6 * Ib);	      	  	    /*calculates the value of R3*/	 
    	Ks = r1 / r2;	  	  	  	  	  	  	    /*calculates the signal amplification*/
    	Vout = Vin * Ks; 	  	  	  	  	  	    /*calculates the output signal*/
    	
    	printf("Resistors:\n");
    	printf("R1 = %10d ohm\n", R1); 
    	printf("R2 = %10d ohm\n", R2);
    	printf("R3 = %10d ohm\n", R3);
    	printf("R4 = %10d ohm\n\n", R4);
    	
    	printf("Output voltage:\n",);
    	printf("Vout = %10.2f v \n", Vout);
    
    	printf("====================");
    	
    	return (0);
    }

  7. #7
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    Hi,

    I was just wondering how I put the code in my message. When I have tried to copy it over it just copies the text and not a screen shot like with yours.

    Thanks

  8. #8
    ATH0 quzah's Avatar
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    There's a note about using code tags at the top of the forum.

    [code] ...your code in here... [/code]


    Quzah.
    Hope is the first step on the road to disappointment.

  9. #9
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    printf("Output voltage:\n",);


    Get rid of this comma and you should be good to go.

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