This program demonstrates how to compare two integers using 8086 inline assembly in C++. By leveraging assembly instructions like sub and conditional jump js, the program determines which number is greater.

#include<iostream.h>
#include<conio.h>

void main() {
    clrscr();
    short a;
    short b;

    cout << "\n Enter First Number:";
    cin >> a;

    cout << "\n Enter Second Number:";
    cin >> b;

    asm mov ax, 0000h        // Clear AX
    asm mov bx, 0000h        // Clear BX
    asm mov ax, a            // Load first number into AX
    asm mov bx, b            // Load second number into BX
    asm sub ax, bx           // Subtract BX from AX
    asm js true              // Jump if result is negative (AX < BX)

    cout << "\n " << a << " is greater than " << b;
    asm jmp end              // Skip 'true' block

true:
    cout << "\n " << b << " is greater than " << a;

end:
    getch();
}

Understanding the Code

Key Assembly Instructions

• mov ax, a: Loads the first number into the AX register.
• mov bx, b: Loads the second number into the BX register.
• sub ax, bx: Subtracts BX from AX.
• js true: If the result is negative (i.e., AX < BX), it jumps to label true.
• jmp end: Skips over the true label if AX >= BX.

Conditional Logic

• If the result of a - b is negative, it means a < b, and the program prints that b is greater.
• Otherwise, it prints that a is greater.

Output

 Enter First Number:5

 Enter Second Number:8

 8 is greater than 5

Output Explanation

When the user enters two numbers:

• If the first number is greater, the subtraction result is positive or zero, and the program prints “a is greater than b”.
• If the second number is greater, the subtraction result is negative, and the program jumps to print “b is greater than a”.