Simple program help

This is a discussion on Simple program help within the C Programming forums, part of the General Programming Boards category; Ok this shouldn't take too long to fix, simple program for working out resistance and voltage for some amplifier... Code: ...

  1. #1
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    Simple program help

    Ok this shouldn't take too long to fix, simple program for working out resistance and voltage for some amplifier...



    Code:
    #include <stdio.h>
    
    
    #define Vc (5.5);
    
    #define Ve (1.1);
    
    #define Vin (0.075);       /* Voltages */
    
    #define Hfe (100);
    
    int main(void)
    {
    	float Vout, R1, R2, R3, R4;
    	float Ic, Vcc;
    	float Ib, Vb, Ks;
    	
    	/* Enter the current, from 2e-3 to 5e-3 */
    	printf("Enter Ic: ");
    	scanf("%f", &Ic);
    	
            /* Enter the voltage, 9.0, 10.0 or 12.0 */
    	printf("Enter Vcc: ");
    	scanf("%f", &Vcc);
    	
            Ib = Ic / Hfe;
    	R1 = (Vcc - Vc) / (Ic);
    	R2 = (Ve / Ic + Ib) ;
    	Vb = 0.7 + Ve;
    	R3 = (Vcc - Vb)/ (6 * Ib);
    	R4 = Vb	/ (5 * Ib);	   
    	Ks= R1/R2; 
    	Vout = Ks * Vin;
    	
    	printf("**********************\n");
    	printf("R1= %6.0f Ohms \n", R1);
    	printf("R2= %6.0f Ohms \n", R2);
    	printf("R3= %6.0f Ohms \n", R3);
    	printf("R4= %6.0f Ohms \n", R4);
    	printf("Vout= %3.1f  V \n", Vout);
    	
    	return(0);
    	}

    Ok, the green lines are the ones I'm having trouble with, the compiler says "error: expected ')' before ';' token" for both the lines
    And also for the red lines, if I swap them around like so
    Code:
    Vb = Ve + 0.7
    Vout = Vin * Ks
    The compiler says "Warning: statement with no effect" and "error: invalid type of 'unary *' " respectively. But if I have them the way I do as above, it works fine.

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    #defines and semicolons; don't mix.

  3. #3
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    haha, wow, I can't believe I missed that. I don't even know why I put them in there
    Thanks for the help

  4. #4
    Woof, woof! zacs7's Avatar
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    Also, it's good to have everything for the pre-processor in caps -- it makes it easier to read.

    For example, I'd think 'Vin' is a variable name at first glance. Constants rather than defines would do well here.

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