How to swap 2 values using only 2 variables..??

Question

Not using any temporary variable

Answer 1

This is a well known trick. But you need to be careful when a+b is overflowing the corresponding data type.
a = a+b;
b = a-b;
a = a-b;

Answer 2

//so many same question already exist , u can search before posting a question
//might be marked as [duplicate] soon
https://www.sololearn.com/Discuss/245511/?ref=app
https://www.sololearn.com/Discuss/564903/?ref=app
https://www.sololearn.com/Discuss/811929/?ref=app