after class with example

;

section01/Lec14/factorial_in_class.asm

+.data
+	prompt: .asciiz "N = "
+	sep:	.asciiz "\n"
+.text
+main:
+	li $v0, 4
+	la $a0, prompt
+	syscall
+
+	li $v0, 5
+	syscall
+	
+	move $a0, $v0
+	
+	jal fact
+	move $s0, $v0
+	
+	li $v0, 4
+	la $a0, sep
+	syscall
+
+	li $v0, 1
+	move $a0, $s0
+	syscall
+		
+	li $v0, 10
+	syscall
+			
+	
+fact:	
+	addi	$sp, $sp, -8
+	sw	$ra, 0($sp)
+	sw	$a0, 4($sp)
+	
+	beq 	$a0, $zero, done
+	
+	addi	$a0, $a0, -1
+	jal	fact
+	lw	$ra, 0($sp)
+	lw	$a0, 4($sp)	
+	mul	$v0, $v0, $a0
+	addi	$sp, $sp, 8
+	jr 	$ra
+	
+done:
+	li 	$v0, 1	
+	lw	$ra, 0($sp)
+	#lw	$a0, 4($sp)
+	addi	$sp, $sp, 8
+	jr 	$ra
+			
+	

section01/Lec14/factorial_start.asm

+.data
+	prompt: .asciiz "N = "
+	sep:	.asciiz "\n"
+.text
+main:
+	li $v0, 4
+	la $a0, prompt
+	syscall
+
+	li $v0, 5
+	syscall
+	
+	move $a0, $v0
+	
+	jal fact
+	move $s0, $v0
+	
+	li $v0, 4
+	la $a0, sep
+	syscall
+
+	li $v0, 1
+	move $a0, $s0
+	syscall
+		
+	li $v0, 10
+	syscall
+			
+	
+fact:	
+	addi	$sp, $sp, -8
+	sw	$ra, 0($sp)
+	sw	$a0, 4($sp)
+	
+	beq 	$a0, $zero, done
+	
+	addi	$a0, $a0, -1
+	jal	fact
+	lw	$ra, 0($sp)
+	lw	$a0, 4($sp)	
+	mul	$v0, $v0, $a0
+	addi	$sp, $sp, 8
+	jr 	$ra
+	
+done:
+	li 	$v0, 1	
+	lw	$ra, 0($sp)
+	#lw	$a0, 4($sp)
+	addi	$sp, $sp, 8
+	jr 	$ra
+			
+