Function headers

[halleyc]

Can someone explain the difference to me about the two function headers with the float & amtC and the float amtC
Consider the following variable definitions and function call:

string customer = "Customer1";
float balance;
float amount = 72.56;
char type = S;
getBalance(customer, balance, type, 200.53);

Consider the two function headers below. For each header, say if you think the header for function getBalance is a valid header, and give reasons for your answer:

3. void getBalance (string customerP, float & balAmnt,char & typeC, float & amtC);
4. void getBalance (string customerP, float & balAmnt,char & typeC, float amtC);

[gunnerfunner]

both headers are valid but for POD like float it'd make more sense to pass by value:
http://stackoverflow.com/questions/2108084/pass-by-reference-more-expensive-than-pass-by-value
depending upon the context, it'd also make sense to const qualify variables wherever possible

[TheIdeasMan]

Also, prefer to use double rather than float - if your assignment allows it. The precision of float is easily exceeded - it can only do 6 or 7 significant figures.

In this:

float amount = 72.56;

the 72.56 is actually a double (the default), so when it is assigned to float amount , there is an implicit cast to convert it to float. One can avoid that by doing float amount = 72.56f; , but it is better to just make the whole thing double in the first place.

Pass string by reference, probably const if it is not to be changed:

void getBalance (const std::string& customerP, 
                 double& Balance, 
                 const char typeC, 
                 const double amtC);

Notice I put the reference right next to the type, in C++ there are many who like to emphasise the type, as C++ is all about types. Also the way I have formatted the code when there are multiple parameters.

What does amtC have to do with getting a balance? What does amtC even mean?

I am not a fan of abbreviating variable names, unless there is a good reason. With balAmnt, the amount part is superfluous ; so what's wrong with just Balance ?

Good Luck !!

[halleyc]

Thank you for your explanation. Unfortunately all we were given is what i wrote in my question. So we just have to look at the code fragment and the two headers and decide which header suits best.
These questions are very ambiguous

[mbozzi]

Only
void getBalance (string customerP, float & balAmnt,char & typeC, float amtC);
Matches the invocation
getBalance(customer, balance, type, 200.53);
Because lvalue references will not bind temporaries.

[halleyc]

thank you