reciprocal calculator in c

Hi all,
Im wondering if I can get some pointers.
I have an assignment for basic "c" programming , a reciprocal calculator with conditions.The conditions being : if entry =0 then print "reciprocal undefined" (this bit I can get!). else (should be) print "the reciprocal = 1/(number entered) or (decimal equivelent). (this bit is frying my head).
please help. this is what I have so far

// reciprocal calculator
// by jf
// date last modified 31/10/10

// include standard input/output from header file h
#include <stdio.h>

// include standard library from header file h
#include <stdlib.h>

// main function heading
main ()

// begining of instructions
{

// declare variables and set initial value to zero
float r=0,a=0,b=0;

// print on screen enter number
printf("Enter number:",&a); (this bit works ok)

// scan for input
scanf("%f",&b); (as does this)

// manipulate variables
r=(1/b); (not sure if im doing this bit right)

// if conditions
if (b==0) printf("Reciprocal undefined\n"); (this bit also works)

// otherwise do this
else printf("the reciprocal of,b,is = 1/,b,or %f\n",&r); ()mad!!!

// pause to view answer
system("PAUSE");
}

 

Using the &, you are sending the memory address of the variable r in the printf statement.

printf

Pointers are typically used for strings.

Try this:

Code ( (Unknown Language)):

1.  
2. #include <stdio.h>
3.  
4. // include standard library from header file h
5. #include <stdlib.h>
6.  
7. // main function heading
8. main ()
9.  
10.         // begining of instructions
11. {
12.  
13.         // declare variables and set initial value to zero
14.         float r=0,b=0;
15.  
16.         // print on screen enter number
17.         printf("Enter number:");
18.  
19.         // scan for input
20.         scanf("%f",&b);
21.  
22.         // manipulate variables
23.         r=(1/b);
24.  
25.         // if conditions
26.         if (b==0) printf("Reciprocal undefined\n");
27.  
28.         // otherwise do this
29.         else printf("the reciprocal of %f, 1/%f is %f\n",b,b,r);
30. }
31.  

Code above compiled and ran on a linux system with no errors.

The float a is not needed in the first printf, and is not used elsewhere in the program.


Output:

Code ( (Unknown Language)):

1.  
2. Enter number:34
3. the reciprocal of 34.000000, 1/34.000000 is 0.029412
4. Enter number:0
5. Reciprocal undefined
6. Enter number:0.3333333333333333333333333333
7. the reciprocal of 0.333333, 1/0.333333 is 3.000000
8. Enter number:-1293
9. the reciprocal of -1293.000000, 1/-1293.000000 is -0.000773
10.