What is abstract and examples of abstracts?

Answer 1

Abstraction is just how closely related a computer language is to the computer's native machine code architecture. Obviously, the bottom of the 'ladder' is the machine code, but you can go even further down with microcode. The higher you go up on the 'ladder', the more "human-like" the code becomes (the code becomes more and more written in english).

Examples:

<main+0>: 01010101 10001001 11100101 10000011 11100100 11110000 10000011 11101100

<main+8>: 00100000 11101000 00011010 01000000 00000000 00000000 1100111 01000100

<main+16>: 00100100 00000100 01110000 01000111 0000000 11000111 00000100

<main+24>: 00100100 10000000 01011111 0100111 00000000 11101000 10100110 10001100

<main+32>: 00000110 00000000 10001101 01000100 00100100 00010100 10001001 0100010

^ Machine code

<main>: push %ebp

<main+1>: mov %esp, %ebp

<main+3>: and $0xfffffff0, %esp

<main+6>: sub $0x20, %esp

<main+9>: call 0x40530c <__main>

<main+14>: movl $0x477024, 0x4(%esp)

<main+22>: movl $0x475f80, (%esp)

<main+29>: call 0x469fac <operator<<>

<main+34>: lea 0x14(%esp), %eax

<main+38>: mov %eax, 0x4(%esp)

^ Assembly language

cin >> celciusTemp;

fahrenheitTemp = celciusTemp * 9 / 5 + 32;

cout << fahrenheitTemp;

^ C++

Believe it or not, but the above machine and assembly language examples convert a value in Celsius to Fahrenheit. The higher up you go on the abstraction ladder, the more the language abstracts away all of the little details from below.