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Starting a program automatically calls the function named
(see The main Function). Aside from that, a function does nothing
except when it is called. That occurs during the execution of a
function-call expression specifying that function.
A function-call expression looks like this:
Most of the time, function is a function name. However, it can also be an expression with a function pointer value; that way, the program can determine at run time which function to call.
The arguments are a series of expressions separated by commas. Each expression specifies one argument to pass to the function.
The list of arguments in a function call looks just like use of the comma operator (see Comma Operator), but the fact that it fills the parentheses of a function call gives it a different meaning.
Here’s an example of a function call, taken from an example near the beginning (see Complete Program).
printf ("Fibonacci series item %d is %d\n", 19, fib (19));
The three arguments given to
printf are a constant string, the
integer 19, and the integer returned by