Computer science: value parameter vs variable parameter
Tutoring computer science, the difference between variable and value parameters is interesting. The tutor illustrates it.
value parameter:
the parameter’s value is sent to the function or method, but the function can’t change the parameter itself. For instance:
j=5
function(value_parameter p){
p=p+1;
output “p=” p;
output “j=” j;
}
function(j);
will give the output
p=6
j=5 //j is still 5
variable parameter
the parameter itself is sent to the function. Changes made to it by the function will persist in the external program.
j=5
function(variable_parameter p){
p=p+1;
output “p=” p;
output “j=” j;
}
function(j);
will give the output
p=6
j=6 //j has been changed to 6 by the function
Source:
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.
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