title: error: expected ';', ',' or ')' before '&' token| on a simple C program found online
body: <p>I found this program online to practice C. When I tried to compile this program in Code blocks, I am getting this error "error: expected ';', ',' or ')' before '&amp;' token| " in two places (mentioned in the codes). It would be really helpful, if someone could explain me the reason for the error. </p>
  
  <pre><code>#include&lt;stdio.h&gt;
  int f1(int x,int y)
  {
  
  x=x+2;
  y=y+3;
  return x+y;}
  int f2(int &amp;x,int y) //error: expected ';', ',' or ')' before '&amp;' token|
  
  {
   x=x+2;
  y=y+3;
  return x+y;
  }
  int f3(int *x,int *y)
  {
  
  *x = *x+2;
  *y = *y+3;
  return *x+*y;
  }
  int f4(int x,int &amp;y,int *z)//error: expected ';', ',' or ')' before '&amp;' token|
  {    x=x+y;
  
   y=*z+3;
  z=&amp;x;
  *z=y*2;
  return *z;
  }
  main()
  {
  int k=3,m=5,r=0;
  printf("1) %d %d %d\n",k,m,r);
  r=f1(k,m);
  printf("2) %d %d %d\n",k,m,r);
  r=f2(k,m);
  printf("1) %d %d %d\n",k,m,r);
  r=f3(&amp;k,&amp;m);
  printf("1) %d %d %d\n",k,m,r);
  r=f4(k,m,&amp;r);
  printf("1) %d %d %d\n",k,m,r);
  
  return 0;
  }
  </code></pre>