Code

 Header...
// Failed attempt to update energy within a function
 void update_energy(double energy){
   ... 

»  energy=energy+10.3;
}

 int main(){
   ... 

»  double energy=1.1;

»  printf("The old energy was: %g\n", energy);
»  update_energy(energy);
»  printf("The new energy is: %g\n", energy);
  
»  return 0;
}

Data