Thread: getting an error ???

Originally Posted by ki113r

Heh , a bit too late for that now , the assignement is due tomorrow

I'm sure there's a Barnes & Noble or Waterstones near you, plus your departmental library should have a copy.

QuantumPete

yeah, well you're trying to print out the aperture value, but do you see aperture in your printf???

QuantumPete

Ok before I hand this in , can someone just please go over my indenting , because I haven't done it before . I assume there isno strict rules , just making the code easier to read. Did I indent the code ok ? Thanks again

Code:

#include <stdio.h>
int main(void)

{

	int exposure=0;		//Initiate the exposure variable - integer 
	float aperture=0;	//Initiate the aperture variable - floating point number
	int choice = 0;		//Initiate the choice variable - used in the while loop 

	printf("\nEnter Exposure Time: ");	// Prompt the user for exposure time
	scanf("&#37;d",&exposure);			// Store exposure time in the exposure variable

	printf("The selected Exposure time is %d\n", exposure);		        // Print the exposure time entered on screen


	// Initiate the while loop


	{


			while (choice<1)
		{
				printf ("Please enter the aperture size - *like so : x.yf*\n");	// Prompt the user for the aperture size.
				scanf("%ff",&aperture);					        // Store the aperture value in the aperture variable. 
		
				if
		  		   (
					   (aperture==1.2f)  || (aperture==1.4f) 
                  			|| (aperture==2.0f)  || (aperture==2.8f)
                  			|| (aperture==2.8f)  || (aperture==4.0f)      // Check to see if the value entered corresponds to one of the values 	                                     || (aperture==5.6f)  || (aperture==8.0f)      // that are allowed.
                  			|| (aperture==11.0f) || (aperture==16.0f)
                  			|| (aperture==22.0f) || (aperture==32.0f)
					|| (aperture==1.8f) 	
				   )	
			{

					printf("You have entered a defined aperture. \nThe aperture value entered is  : %.1ff\n",aperture);
	
					choice=2; // Set the choice variable to 2 to provide a condition for exit of the loop. 
			}
	
					
			                else

	
			{
					printf("You have entered aperture value of %.1ff. \n This is an invalid aperture, please try Again\n", aperture);							     // Alert the user that incorrect value was entered.
			
					choice=0; // Set the choice variable to 0 so that condition is still true - and the program will loop.
			}	



		}


	}


}

Apertures are "f5.6" not "5.6f" (I think the absolutely correct way to write apertures is f/5.6, because that is exactly what the aperture represents, the focal-length divided by 5.6 is the size of the opening of the lens). Obviously the number 5.6 could be any of the numbers listed (and others). So you need to use "f%f" in your scanf call. Remeber to change the explanatory text too!

You have an extra set of braces around your while-loop. They serve absolutely no purpuse.

The while is indented further than the brace corresponding to the while - I prefer to have them equal or braces further in.

You have 2.8 twice in the list of valid f-values. You are missing 5.6 and 8 on the other hand. It would be good to have 1.8 close to the front, rather than at the back end (otherwise you look at it quickly and think it's missing).

Why can't "choice" (which should probably be called "valid") be 0 and 1 only - there's no reason for it to be 0 and 2. Just set it to 0 and use while(!valid). Set to 1 when correct value has been entered, don't change it if an incorrect value has been entered.

--
Mats

/Edit That aperture==f4.0 is in fact in line with the rest of the values in my code .

I changed some thins now .However I get quite a few errors .

Code:

{
^
test5(27) : Error: '(' expected following if
                                           (aperture==f1.2)
                                                         ^
test5(29) : Error: undefined identifier 'f1'
                                        || (aperture==f1.4)
                                                         ^
test5(30) : Error: ')' expected
                                        || (aperture==f1.8)
                                         ^
test5(31) : Error: '=', ';' or ',' expected
                                else
                                   ^
test5(52) : Error: '=', ';' or ',' expected
Fatal error: too many errors
--- errorlevel 1

Here is my code :

Code:

#include <stdio.h>
int main(int argc, char * argv[])

{


// Mainline Variable Declarations
FILE * output = stdout;
FILE * input = stdin;



	int exposure=0;		//Initiate the exposure variable - integer 
	float aperture=0;	//Initiate the aperture variable - floating point number


	fprintf(output,"\nEnter Exposure Time: ");	// Prompt the user for exposure time
	fscanf(input,"&#37;d",&exposure);			// Store exposure time in the exposure variable

	

                           
				fprintf(output,"Please enter the aperture size - *like so : fx.y*\n");	// Prompt the user for the aperture size.
				fscanf(input,"f%f",&aperture);					        // Store the aperture value in the aperture variable. 
		
			if
{
		  		   (
					   (aperture==f1.2) 
                                        || (aperture==f1.4) 
                                        || (aperture==f1.8) 
                  			|| (aperture==f2.0)  
                                        || (aperture==f2.8)                                                                                                                                          || (aperture==f4.0)      // Check to see if the value entered corresponds to one of the values 	                                                          || (aperture==f5.0) 
                                        || (aperture==f8.0)      // that are allowed.
                  			|| (aperture==f11.0) 
                                        || (aperture==f16.0)
                  			|| (aperture==f22.0) 
                                        || (aperture==f32.0)
						
				   )
	
			{

					fprintf(output,"You have entered a defined aperture.\n")
					fprintf(output,"::::::Values::::::Entered::::::\n\n")
					
					fprintf(output,"The selected Exposure time is %d\n", exposure);         // Print the exposure time entered on screen
					fprintf(output,"The selected Aperture is  : f%.1f\n",aperture);		// Print the aperture on screen
		

			}	

		
				else
			


			{
					fprintf(output,"You have entered aperture value of f%.1f. \n", aperture)
					fprintf(output,"This is an invalid aperture, the program will now exit\n") 								                     // Alert the user that incorrect value was entered.
			                break;
					
		        }


}

I really can't see any problems with that code. Help please

f1.2 isn't a float, etc. etc..

ki113r you seem to ignore 99% of what people say and go off and do your own thing, hence the size of this thread. Consider taking a minute to read what other people have to say...

f goes in the beginning only in strings. That's the syntax for f-stops in the field of photography.

Code:

printf("my camera is set to f1.0");

f goes at the end for floats. that's the syntax for C and C++.

Code:

float float_val = 1.0f;
printf("my camera is set to f%f",float_val);

/*or with a constant*/
printf("my camera is set to f%f",1.0f);

Yes, I suppose I should have pointed out the difference between the f in C and the f in photography. It's just pure coincidence that they are very similar - well, the fact that the words "Focal Length" and "float" both start with the letter F is what makes them similar.

--
Mats