Can someone help me understand the ++x, x++, - - x, and x-- thing I still have some problems with it \\fell free to upvote,comnt

Answer 1

++x increase x and return increased value. x++ increase and return old value.
-- do the same, but with desrease

Answer 2

example1
int x = 0;
x++; (now x = 1)

example2
int x = 0;
int y = x++; (now x = 1; but y=0;)
why y = 0? because with x++ it first evaluates the expression then it increases the value

example3
int x = 0;
int y = ++x; (now x = 1; y=1;)
why y = 1? because with ++x it first increases the value then it evaluates the expression;

Similarly when --x or x--.

Try it for yourself:

example4:
int x = 100;
int y = 1+x--; y - ?

example5:
int x = 1;
int y = 500*--x; y - ?

Answer 3

Postfix notation(e.g. a++, a--) is like a postpaid card increment or decrement will happens after performing the operations like assign or print.

Prefix notation(e.g. ++a, --a) is like a postpaid card increment or decrement will happens first then performing the operations like assign or print.

Ex. Program with output:

#include <iostream>
using namespace std;

int main()
{
int a=10;
cout<<"\nA="<<a--;
cout<<"\nA="<<--a;
cout<<"\nA="<<a++;
cout<<"\nA="<<++a;
return 0;
}

A=10
A=8
A=8
A=10

Note:
First output prints the value(A=10) and decremented the value of A by 1.
Value of A will be 9 in the memory.
Second output decrements the value of A by 1 and prints the value(A=8).
Value of A will be 8 in the memory.
Third output prints the value(A=8) and increment the value of A by 1.
Value of A will be 9 in the memory.
Fourth output increments the value of A by 1 and prints the value(A=10).
Value of A will be 10 in the memory.

Answer 4

This means when I use x++ the value of x stays the same?

Answer 5

no, the value doesn't stay the same. it is altered in memory but in an expression, the value would be the initial x, the increasing taking place after evaluation. with ++x it first increases the value then it evaluates the expression

Answer 6

--x and ++x are called prefixes while x-- and x++ are postfixes. Prefixes increment or decrement the variable before it's used, postfixes change the value after it was used.

Answer 7

So, basically ++ or -- before a variable (++x or --x) is prefix. So, it performs the function before the variable is used.

++ or -- after a variable(x++ or x--) is postfix. So, it performs the function after the next use of variable in the statements.

Answer 8

After execution of x++ the value x will increase after
I.e x=1,x++
output will be 2

After execution of ++x the value x will increase before
i.e x=1,++x
output will be 2 but before execution of x