Specifying float or double yet getting int value - c

Question

#include <stdio.h>
int diameter_fn(int r)
{
return (2 * r);
}
void circumference_fn(int r)
{
float pie = 22 / 7;
float circum = (2 * pie * r);
printf(", Circumference = %f", circum);
}
void area_fn(int r)
{
float pie = 22 / 7;
float area = (22 * r * r / 7);
printf(" & the Area = %f", area);
}
int main()
{
printf("\nName = Parth_Agrawal & UID = 22BCS10924\n");
int radius;
printf("Enter the Radius of Circle:\t\t");
scanf("%d", &radius);
printf("\nDiameter = %d", diameter_fn(radius));
circumference_fn(radius);
area_fn(radius);
return 0;
}
I want to calculate Circumference, diameter and area of circle using functions yet I get non-perfect Circumference and area values.
I already tried replacing the float with double, %f with %lf etc but I am always getting the Circumference and area in xxx.0000 format,I.e, similar to Int converted to float format.
Like the area for 4 unit radius is 50.27 but it is giving me 50.000000 which is too much annoying.
This is the Result I am getting
whereas this is the Result which I should get

Answer 1

... but it is giving me 50.000000 ...
OP is using integer math in many places where floating point math is needed.
void circumference_fn(int r) {
float pie = 22 / 7; // Integer math!!
float circum = (2 * pie * r);
printf(", Circumference = %f", circum);
}
void area_fn(int r) {
float pie = 22 / 7; // Integer math!! pie not used
float area = (22 * r * r / 7);// Integer math!!
printf(" & the Area = %f", area);
}
Instead use FP math.
Scant reason to use float. Use double as the default FP type.
Rather than approximate π with 22/7, use a more precise value.
#define PIE 3.1415926535897932384626433832795
void circumference_fn(int r) {
double circum = (2 * PIE * r);
printf(", Circumference = %f", circum);
}
void area_fn(int r) {
double area = PIE * r * r;
printf(" & the Area = %f", area);
}
Other
All three functions should take a double argument and return a double.
Use "%g" for printing. It is more informative with wee values and less verbose with large ones.

Answer 2

#Shawn is right: you are using integer math to calculate Pi. You should #include <math.h> and use M_PI instead of trying to calculate it yourself.