Question

Write a MARIE program that asks the user for a beginning and an ending address of an array in the memory and checks whether the sequence of integers in between these memory locations is a palindrome. Output 1 on the screen if you conclude it is a palindrome. Add comments to your program.

Answer 1

Input
Store X //input and store the beginning address of array in X
Input
Store Y //input and store the ending address of array in Y

Loop, LoadI X //Load the value at address X of array through indirect addressing mode in the accumulator(AC)
Store N   // store the value at address X in a variable N
LoadI Y       //Load the value at address Y of array through indirect addressing mode in the accumulator(AC)
Subt N       // subtract value at address X with value at address Y to check for palindrome
Skipcond 400   // if AC=0 then skip the next instruction else continue
Jump NegOP

Cond,  Load X //load Address X in AC
Add One       // increment the address by 1 for next index of array
Store X       // store in X after incrementing
Load Y       //load Address Y in AC
Subt One   // decrement the address by 1 for next index of array to check for palindrome
Store Y       //store in Y
Subt X       // checking the condition for arrray index out of bounds
Skipcond 800 // if AC>0 then skip next instruction and continue checking for the palindrome
Jump OP
Jump Loop

NegOP, Load Zero // loading zero in AC and printing to indicate that string is not a palindrome
Output
Halt
OP, Load One
Output
Halt
// local variable declarations
X, Dec 0
Y, Dec 0
N, Dec 0
One, Dec 1
Zero, Dec 0