The task is to find the angle of a triangle in C?

Question

C++ / C#

you need to write a program in C that finds the beta angle and the median knowing the sides a, b, c (entered from the keyboard)
According to the conditions of the problem, a = 13.2, b = 10.8, c = 8.37.
I wrote like this:

#include <stdio.h>
#include <math.h>

#define PI 3.14159265

int main() {


  float a, b, c, m;
  long float res;
  printf("a = ");
  scanf("%f",&a);
  printf("b = ");
  scanf("%f",&b);
  printf("c = ");
  scanf("%f",&c);

  res = acos((a * a + c * c - b * b)/(2 * a * c));
  m = 1 / 2 * sqrtf(2 * a * a + 2 * b * b - c * c);
  printf("%f\n", res);
  printf("%f\n", m);

  return 0;
}

but instead of the angle it gives me 0.95 ..., and the median is generally 0.0000

Answer 1

acos returns radians:
Returns the principal value of the arc cosine of x, expressed in radians.
About the median - most likely something with types (not sure, try writing 1.0f in the numerator)

Answer 2

m = 1 / 2 * sqrtf(2 * a * a + 2 * b * b - c * c);
The point is the priority of arithmetic operations and the features of integer division operations .
1/2 = 0, hence the problems.
Change to
will fix the situation.
You can convert a number from radians to degrees like this:
res = 180*acos(...)/PI;