Question

In assembly language computer programming 1. create a 5 element array
2.prompt the user to enter 5 numbers to fill the array
3. exchange the number at position 1 with the number at position 4 of the array. (Don't forget that array positions are counted from zero, in our case 5 element array positions are counted 0,1,2,3,4.)
4.Display the array numbers 1 and 4 to show that you did the exchange correctly. Show a message like "The number at position 1 is" and display the number , so that the user knows what each number represents.Do the same for displaying the number at position 4 of the array.

Answer 1

^{Answer-1
There are two ways to define an array in assembly language:-
A.
An initialized array is defined in the same way as a scalar variable, but with multiple initial values.
Example-
       Array DB 1,2,3,4,5
       Array is The name of array and DB (Data Byte) , DW (Data Word) are it’s type.}
  

^{B.
Uninitialized arrays are defined using the .space directive.}

^{Note:-
The .space directive allocates the specified number of bytes. Specifying the desired number of array elements is a common mistake.
   scores: .space 400
and also
Now, If we want to declare an array with assigning no value initially then it will be}

^{Array_Name Data_Type Number_Of_Index DUP(?)}

^{To access an array in assembly language, we use a pointer.
A pointer is simply a register or variable that contains a memory address.}

^{Assembly Code:-}

^{.MODEL SMALL
.STACK 100h
.DATA
ARR DB 1,2,3,4,5 ;array declaire
.CODE
MAIN PROC
MOV AX,@DATA
MOV DS,AX
  
MOV CX,5
MOV SI,0
MOV AH,2
  
OUTPUT:
MOV DL, ARR[SI]
ADD DL,30H
INT 21H
INC SI
LOOP OUTPUT}

^{MAIN ENDP
END MAIN}

^{Answer-2
.MODEL SMALL
.STACK 100h
.DATA
ARR DB 20 DUP(?) ; declaire array with null value initially}

^{.CODE
MAIN PROC
MOV AX,@DATA
MOV DS,AX
XOR BX,BX
XOR CX,CX
  
PRINT "How many number you want to store(1-5): "
  
MOV AH,1
INT 21H
AND AL,0FH ;convert from ascii value to real value
  
MOV CL,AL
MOV BL,AL
MOV SI,0
  
PRINTN
PRINT "Enter values(without press enter or space): "
PRINTN
INPUT:
INT 21H
MOV ARR[SI],AL
INC SI
LOOP INPUT
PRINTN
PRINT "OUTPUT: "
PRINTN
  
MOV CX,BX
MOV SI,0
MOV AH,2
OUTPUT:
MOV DL,ARR[SI]
INT 21h
INC SI
LOOP OUTPUT
  
MAIN ENDP
END MAIN}

^{Answer 3}

^{DATA SEGMENT
A DB 1,2,3,4,5
B DB 6,7,8,9,10
DATA ENDS
CODE SEGMENT
ASSUME DS:DATA,CS:CODE
START:
MOV AX,DATA
MOV DS,AX
MOV CX,0000
MOV CL,05
LEA BX,A
LEA SI,B
L1:MOV DH,BYTE PTR[BX]
MOV DL,BYTE PTR[SI]
MOV BYTE PTR[BX],DL
MOV BYTE PTR[SI],DH
MOV DH,BYTE PTR[BX]
MOV DL,BYTE PTR[SI]
INC BX
INC SI
DEC CL
CMP CL,00
JNZ L1
MOV AH,4CH
INT 21H
CODE ENDS
END START}