text: #include <stdio.h>
  #include <string.h>
  unsigned int fibch(unsigned int n)
  {
      if (n<2)
       return n;
      else
       return fibch(n-1)+fibch(n-2);
  }
  int sum_array (int a[],int n)
  {
      if (n==1)
       return a[0];
      else
       return sum_array(a,n-1)+a[n-1];
  }
  int occur(char *s,char c)
  {
    if (*s=='\0')
     return 0;
    else
      if (*s==c)
       return occur (++s,c)+1;
      else
       return occur (++s,c);
  }
  void reverse (int a[],int n)
  {
      if (n/2==0 && n%2==1)
       {
  
          return  ;
       }
      else
       {
         a[0]+=a[n-1];
         a[n-1]=a[0]-a[n-1];
         a[0]=a[0]-a[n-1];
         return reverse (++a,--n);
       }
  }
  void main ()
  {
      system("cls");
      unsigned int a;
      scanf ("%d",&a);
      a=fibch(a);
      printf ("\nfibonacci=%d",a);
      int b[]={1,2,3,4};
      printf ("\nSum array= %d",sum_array(b,4));
      char str[]={"Hello world"};
      char ch='o';
      printf ("\nNumber o in Hello world %d",occur(&str,ch));
      reverse (b,4);
      for (a=0;a<4;a++)
       printf ("\n%d ",b[a]);
  }
  