DMP - Chapter 9

Functions

Use function:

to do one task
to avoid writing duplicate code
to make code modular, hence easier to read and debug

Local variable, global variable, static variable

#define LIMIT 40
void separator(void)
{
	int i;
	for (i = 0; i < LIMIT; i++)
		putchar('*');
}

Function arguments

void separator_1(int total)
{
	int i;
	for (i = 0; i < total; i++)
		putchar('*');
}

void separator_2(int total, char ch)
{
	int i;
	for (i = 0; i < total; i++)
		putchar(ch);
}

Functions returning a value

float fmax(float x, float y)
{
	if (x >= y)		/* OR return((x >= y) ? x : y); */
		return(x);
	else
		return(y);
}

Function type, declaration, prototype, and definition

Recursion

Multiple functions / files

Address operator: & (Lisitng 9.13)

Pointer type stores addresses: e.g. int *ptr

Indirection operator: * (Lisitng 9.13a)
when followed by an address, * gives the value stored at that address.

Passing arguments to functions by address (swap.c)

word_count.c

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