S.no Call By Value Call By Reference
1. Passing variable values when calling a function is called Call By Values Passing variable location when calling a function is called Call By Reference
2. Values of calling function variable to get copied into dummy variables Address of actual variables get copied into the dummy variables
3. Changes have no impact on values of actual variables Changes can manipulate real variables
4. Cannot alter the values of actual variables Possible to alter the values of variables
BY Best Interview Question ON 06 Feb 2019