Calculate Average in C program

[BoanHed]

I want to make a C program with a graphical interface that must be composed of 11 numbers (averages) with a "calculate" button that allow the calculation of the number.

[Walby]

for(j = 0, j < 11, j++)
{
  do
  {
    
  }  while 
  F[j] = input;
  sum += input;
}
if(sum != 1.0)
  
else
{
  for(j = 0; j < 11, j++)
   Avg += (F[j]*X[j]);
  Avg /= 11;
  // output Avg
}

[Zecho]

// Calculating the average

#include <iostream> 
using namespace std; 

int main() 
{ 
    cout << "Enter the number: "; 
    int i; 
    cin >> i; 
    double num; 
    double sumnum; 
    sumnum = 0.0; 
    for (int y = 1; y <= i; y++) 
    { 
        cout << "#" << x << " = "; 
        cin >> num; 
        sumnum += num;        
    }

[Aberto]

#include <stdio.h>

float average(float z, float d) {
   return (z + d)/2.0f;
}

/* main program - execution always starts here */
void main() {

   float average(float x, float y);  /* Function prototype */

   float val1= 1.0F;
   float val2 = 2.0F;
   float o = 0.0F;


   o = average(val1, val2);
   printf("\nThe average is: %f",  o);
}