I want to understand this code

Question

a=3;
b=2;
b=a++;
cout<< b++;

Why this gives 4 it shouldn’t be 5??

Answer 1

a=3;
b=2;
b=a++;//b=3 and a=4
cout<<b++;//first print value of b means 3 and then incremented by 1 means b=4
cout<<b++;//print 4 but value of b is 5

Because it is postfix(b++) operator

Answer 2

Ipang I was wondering same, the output must be 3 neither 4 nor 5.

Answer 3

Rembrand Paul Pardo

https://code.sololearn.com/c58949uJx1jw/?ref=app

Answer 4

b=a++ it is mean add a value to b and add +1 to a after
Naw b=3 ,a=4
after that copy b++ mean 3+1

Answer 5

I tested the code in Code Playground and got 3 as output (as I expected).

Answer 6

Hello_World Your explanation is correct but since there is only single cout statement so the final output will be 3

Answer 7

Its answer is 3 not 4 or 5

Answer 8

nAutAxH AhmAd
We'll have to wait for the OP to confirm that I guess : )

Answer 9

nAutAxH AhmAd I know ,Just written to understand

Answer 10

Buddy i think the output should be 3 not 4 and not 5. Let see how??

a=3;
b=2;
b=a++;//it is post increment so, first assign then increment i.e. b=3 and a=4
cout<< b++;//now same it is also post increment i.e. first it will print the value of b i.e. b=3 and then increment it by 1.

Answer 11

consider this "b = a++ " -> as "b = a ; a++ ". It works like this,just a matter of prefix and postfix.

Answer 12

Instead of cout <<b++;
Write cout<<++b; for Ans=5

Answer 13

It should be 3.

Answer 14

This code gives 3 as output.
If you will print a then it should gived 4 as output.

Answer 15

cout<<b++ means first cout and then b++
if cout << ++b means first b+=1 and then cout b

Answer 16

a++, while it does increment a, returns the value of it before - not after - it was incremented. The snippet "a = 999; b = a++;" therefore sets b to 999, not 1000. If you want it the other way, use ++a instead, which returns the real, incremented value of a.

Answer 17

Try this way. You'll get 5 as output.

#include <iostream>
using namespace std;

int main(){

int a=3;
int b=2;

b += a;
cout<< b++;

}

Answer 18

b = 2. Then b = 3 and on the next line it will be 4. Now both a and b are 4. On the cout, b is 4, but if you use it again, b will be 5.

b++ increments the value AFTER the line ran.

Answer 19

because -> a++ = a+1
++a = 1+a
so if you entered :
b = a++ means b= a and a= a+1
but if you entered :
b= ++a means b=1+a and a=a

Answer 20

b=a++ this means b is 3 because of the postfix so when you run the code b is increased by 1