You may pass variables to functions either by address or by value. If you pass a variable by address, then both functions will see the changed value of the variable (if the value changes). If you pass a variable by value, you’re really passing a copy of the variable, and the calling function will not see the changed value of the variable (if the called function changes its value).
Of note in this example:
We pass a variable by prepending the variable name with an ampersand (&).
The receiving function (in this case, do_fun()), prepends the variable name with an asterisk (*). This tells the receiving function that it’s receiving the variable’s address, not a copy of the variable.
Notice that the new value of the variable amt is visible in the do_fun() function and in main().
Here is the code:
