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\begin{verbatim}
4. Program for Counting the number of occurences of a character in a string

	program CountC
	implicit none
	INTEGER::CountChar 
	character(len = 30):: a
	character:: ch;

	write(*,*) "ENTER THE INPUT STRING"
	read(*,*) a;
	
	write(*,*) "ENTER THE CHARACTER TO LOOK FOR"
	read(*,*) ch

	print *, CountChar(a, 30, ch)
	end program

	INTEGER FUNCTION CountChar(b, size,c ) 
	INTEGER, INTENT(IN)::size
	CHARACTER(len =size)::b
	character, INTENT(IN)::c
	INTEGER :: L, i
	CountChar = 0;
	L = len(trim(b));
	
	do i = 1, L
 	   if ( b(i:i)==c) then
      	    CountChar = CountChar + 1;
	   endif
        end do
       end function CountChar


5. Program for finding the factorial of a number

	Program MyFactorial
	implicit none
	
        integer:: factorial
	integer:: n
	
	Write(*,*)"Enter A positive number" 
	read(*,*) n
	if (n<0) then 
   		print *,"Factorial is not defined for negative numbers"
	else 
  	print *, "The factorial of", n, " is ", factorial(n)
	endif  
	end Program MyFactorial

	Recursive function factorial(N) result(ans)
	implicit none
	integer:: N
	integer:: ans
  	
	if (N==0) then 
  		ans = 1;
	else 
  		ans = N * factorial(N-1)
	endif
	end function factorial

6.program for finding the nth fibonacci number

	PROGRAM fibonacci
	IMPLICIT NONE 
	INTEGER::n, RFIB, IFIB

	WRITE(*,*) "Please enter the Number:"
	READ *, n;
	WRITE(*,*) n,"th Fibonacci number is:", RFIB(n);
	WRITE(*,*) n,"th Fibonacci number is:", IFIB(n);
	END PROGRAM

	INTEGER FUNCTION IFIB(n)
 	!This is the iterative version of the fib series.
 	INTEGER, INTENT(IN):: n
	 INTEGER::f0, f1
 	INTEGER:: i
 	f0 = 0;
 	f1 = 1;
 	DO i = 2, n
 		IFIB = f0 + f1;
 		f0 = f1;
 		f1 = IFIB;
 	END DO
 	RETURN 
	END FUNCTION IFIB


	RECURSIVE FUNCTION RFIB(n) RESULT(ans)
 	IMPLICIT NONE
 	INTEGER::n, ans
 	
	IF (n==0) THEN
		ans = 0;
 	ELSE IF (n==1) THEN
		ans = 1;
	ELSE
		ans = RFIB(n-1)+ RFIB(n-2);
 	ENDIF
	END FUNCTION RFIB


7. This is the program to find GCD of two numbers

	PROGRAM GCD
	IMPLICIT NONE
	INTEGER:: IGCD, RGCD
	INTEGER:: num1, num2, tmp
	WRITE(*,*) "ENTER THE TWO NUMBERS"
	READ*, num1
	READ*, num2
	WRITE(*,*) "GCD OF", num1, num2, "IS:", RGCD(num1, num2) 
	END PROGRAM 

	!Iterative method for finf=ding GCD
	INTEGER FUNCTION IGCD(num1, num2)
	IMPLICIT NONE
	INTEGER, INTENT(IN):: num1, num2
	INTEGER:: tmp, n1, n2
	n1 = num1;
	n2 = num2;
	DO
	  IF(n1==0) THEN 
   		IGCD = n2;
        	EXIT
  	  ELSE IF(n2<n1) THEN
		tmp = n1;
		n1 = n2;
		n2 = tmp;
  	  ELSE
		n2 = MOD(n2,n1)	
  	  END IF 
	END DO
	END FUNCTION IGCD

	RECURSIVE FUNCTION RGCD(n1,n2) RESULT(ans)
	!Recursive version of the GCD Procedure.
	IMPLICIT NONE
	INTEGER::n1,n2
	INTEGER tmp1, tmp2, tmp;
	INTEGER::ans
	 
	IF(n1 .EQ. 0) THEN
  		ans = n2;
	ELSE IF(n2 < n1) THEN
  		tmp1 = n1;
  		tmp2 = n2;
  		ans = RGCD(tmp2,tmp1)
	ELSE 
 		tmp = MOD(n2,n1)
 		ans = RGCD(n1, tmp)
	END IF 
	END FUNCTION RGCD

\end{verbatim}
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