Help

[DrJones]

Im trying to get this program to work, it stops at

else


WHat have i done wrong here, i want to be able to specifiy whether fahrenheit or celsius can be used.

Regards

#include <stdio.h>


int main()

{
float fahrenheit, celsius;
int a;

printf("Enter a value of 1 for Celsius, 2 for Fahrenheit:\n");
scanf("%d", &a);


if (a == 1)

printf("Enter a degrees in Celcius:\n");
scanf("%f",& celsius);
fahrenheit = 1.8*celsius + 32.0;
printf("Fahrenheit = %f\n", fahrenheit);

else
printf("Enter a degrees in Fahrenheit:\n");
scanf("%f", & fahrenheit);
celsius = (fahrenheit - 32) * 5 / 9;
printf("Celsius = %f\n", celsius);

return 0;


}

[geqo]

err, you need to use code tags, learn c and use brackets:

#include <stdio.h>

int main() { 
    float fahrenheit, celsius;
    int a;

    printf("Enter a value of 1 for Celsius, 2 for Fahrenheit:\n");
    scanf("%d", &a);

    if (a == 1) {
        printf("Enter a degrees in Celcius:\n"); 
        scanf("%f",& celsius);
        fahrenheit = 1.8*celsius + 32.0;
        printf("Fahrenheit = %f\n", fahrenheit);
    } else {
        printf("Enter a degrees in Fahrenheit:\n");
        scanf("%f", & fahrenheit);
        celsius = (fahrenheit - 32) * 5 / 9;
        printf("Celsius = %f\n", celsius);
    }
    return 0;
}

[DrJones]

thanks, ive copyed your text it works, im trying to update mine, still compiling error, ill try and fix it properly..

thanks!!!!

[GanglyLamb]

Just to let you see how vulnerable your code is.

If someone types for int a; "hello" then according to your code the app will skip the Celcius part and go directly to the fahrenheit part....
So look up these functions: isalpha and isdigit.
This way some "dumb" user wont say that your program doesnt do what its supposed to do.

[********]

i'd do it like this...............

#include <stdio.h>

void Celcius (void);
void Fahrenheit (void);

float fahrenheit, celsius;

int main() {
    
    int a;

    clrscr();      /*clears the screen*/
    
    printf("\nEnter a value of 1 for Celsius, 2 for Fahrenheit: ");
    a=getch(); /*alternative to scanf, gets entry from keyboard*/

   switch(a){
  case '1' : Celcius();
                 break;
  case '2': Fahrenheit();
	break;
  default:  printf("\n Please select a valid option");
	 break;
   }

  getch();
  return 0;

}

void Celcius (void){


	printf("\nEnter a degrees in Celcius: ");
	scanf("%f",& celsius);

	fahrenheit = 1.8*celsius + 32.0;
	printf("Fahrenheit = %f", fahrenheit);

}

void Fahrenheit (void)
{
	printf("\nEnter a degrees in Fahrenheit:");
	scanf("%f", & fahrenheit);
	celsius = (fahrenheit - 32) * 5 / 9;
	printf("Celsius = %f", celsius);
}

.......but thats me anyway

[Vber]

Neither getch() or clrscr() are ANSI.

[Prelude]

>int main()
int main ( void ) is more correct.

>clrscr(); /*clears the screen*/
Are you sure? Without a definition, this function could do anything. Why not include conio.h and ensure that this line works. Also note that anything in conio.h is nonstandard and may not exist on your implementation.

>a=getch(); /*alternative to scanf, gets entry from keyboard*/
getch is also defined in conio.h. The comment is also misleading, scanf is considerably more complicated and powerful than getch, so getch would really be an alternative to

scanf ( "%c", &a );

Another thing to note is that stdin isn't always the keyboard.

>scanf("%f",& celsius);
Always check the return value of functions that accept outside input. The chances of getting invalid data are huge.

>scanf("%f", & fahrenheit);
Ditto

>float fahrenheit, celsius;
You really should avoid global variables when you can. If you must use them, try to give them file scope only by declaring them as static.

>int a;
A more descriptive name is in order.

#include <stdio.h>

static double Celcius ( void );
static double Fahrenheit ( void );

int main ( void )
{
  int option;
  
  printf("1) Celsius\n2) Fahrenheit\nChoose an option: ");
  option = getchar();
  
  switch ( option ) {
  case '1':
    printf ( "Celsius = %f\n", Celcius() ); 
    break;
  case '2':
    printf ( "Fahrenheit = %f\n", Fahrenheit() );
    break;
  default:
    printf("Invalid option\n");
  }
  
  (void)getchar();
  return 0;
}

double Celcius ( void )
{
  double celsius;

  printf ( "Enter a degrees in Celcius: " );

  if ( scanf ( "%lf", &celsius ) != 1 )
    return 0.0;
  
  return 1.8 * celsius + 32.0;
}

double Fahrenheit ( void )
{
  double fahrenheit;

  printf ( "Enter a degrees in Fahrenheit:" );

  if ( scanf ( "%lf", &fahrenheit ) != 1 )
    return 0.0;

  return ( fahrenheit - 32.0 ) * ( 5.0 / 9.0 );
}

-Prelude