Thread: Newbie Code question. Where did I go wrong?

Very very new to C, and any help is appreciated. I am attempting to write a basic code to get the perimeter or a triangle. When I use input of 10.2, 10.3, and 10.4 i get back 30.899998 instead of the expected 30.9. Did i make a mistake somewhere? Below is the code i used.

Code:

#include <stdio.h>
 
int main ()
{
  /* variable definition: */
  float base, sidea, sideb, perimeter;
  /* Prompt user for base */
  printf("Enter the base of the triangle: \n");
  // Input the base
  scanf("%f", &base);
  /* Prompt user for sidea */
  printf("Enter the length of sidea of the triangle: \n");
  // Input the sidea
  scanf("%f", &sidea);
    /* Prompt user for Sideb */
  printf("Enter the length of sideb of the triangle: \n");
  // Input the sidea
  scanf("%f", &sideb);
  // Calculate the Perimeter
  perimeter= (base + sidea + sideb);
  // Print the result
  printf("Perimeter is : %f\n", perimeter);
  return 0;
}

Thanks for the help.

Thank you very much. Super helpful.

Hi flecsy

I'am too new on this board, I saw your program and type the code in and the result is 30.9000.
The compiler is Newbie, and is freeware. I was courius, and give it a try.
I have absolutely no idea why mine result is correct.

If I use %.6f a fault in the answere, after the input 10.2 in line(base), line (sitea) and line (siteb) they become direct printed, no input for basea.
the answere is 20.5.
I must write %2.2f or %2.6f, then no mistakes.

John.c
Your statement is correct, If I use only %f, the answere is 30.900000 . If I change it to %.6f, the answere is the same, 30.900000 .
If I change to %.1f the answere is 30.9 . This changes only in the last printf line.

Flescy
Thank you for your file. there is a small piece of C much more clear for me.