Programming a branching computing process?

Question

C++ / C#

There is pract. task:

PROGRAMMING OF A LINEAR COMPUTING PROCESS something like the beginning will turn out, but in the branching I can’t understand the principle of if and else, and also I don’t know how to put the subscript of the function. In general, picrl:
I know for someone who understands C ++ it will look funny, but still ..

#include<stdio.h>
#include<math.h>
int main()
{
double y,x,f(x),f[1](z),f[2](z),f[3](z),z,c;
    y=f(x);
    f(x)=pow(x,4)+2*sin*pow(x,2);
    c=3.2;
    z=cos(c);
    x=(f1(z)*f2(z)*f3(z));
  if (z<0)		
{
    f[1](z)=sin*z+tg*z;
    printf("\nx=%f,y=%f,x,y")
}
else
  if (0<z<8)
{
    f[2](z)=pow(cos,3)*z+3/z;
    printf("\nx=%f,y=%f,x,y");
}
else
  if (z>8)
{
    f[3](z)=pow(z,2)+log*pow(z,2);
    printf("\nx=%f,y=%f,x,y");
}
else
  printf("\n Действительные корни отсутствуют.");
    getchar();	
}

Answer 1

So the task is not to write a C / C ++ program, but to draw a flowchart.
And if you want to write in C, it's better to learn the language first.
And, by the way, there is an error in the problem, for z = 0 the function f2(z) goes to infinity.

spoiler

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

double f(x) {
  double x2 = x * x;
  return x2 * x2 + 2 * sin(x2);
}

double f1(z) {
  return sin(z) + tg(z);
}

double f2(z) {
  double cz = cos(z);
  return cz * cz * cz + 3/z;
}

double f3(z) {
  double z2 = z * z;
  return z2 + log(z);
}

int main() {
  double c = 3.2;
  double z = cos(c);
  double x;
  if (z < 0) {
    x = f1(z);
  } else if (z < 8) {
    x = f2(z);
  } else {
    x = f3(z);
  }
  double result = f(x);
  printf('%f\n', result);
}