Notes on Lab 17: in and out parameters
I.
void replacewithdouble(int * num);
replacewithdouble needs a value for num in order to do the calculation.
So num is an in parameter.
But then the doubled value goes back to main by num, so num is also an out parameter.
To use replacewithdouble:
in main need a variable with a value
int i=5;
then call replacewithdouble(&i);
void justdouble(int x);
x is an in parameter, but there is no out parameter here so the answer is lost and never goes to main.
II
int makechange( int amount, int* q, int* d, int* n, int* p);
amount is an in parameter
q, d, n, p are out parameters only, but the arguments passed to them must be set up ahead of time so there
is someplace for the answers to go.
There is also a return value which can be copied to yet another variable.
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