html> DMP - Chapter 5

DMP - Chapter 5

Operators, Expressions, and Statements

while loop

#include <stdio.h>
#define TWELVETH_ROOT 1.059463094
#define START 440
#define END   880

void main(void)
{
  float pitch = START;
	
	while (pitch < END)
	{
		pitch = pitch * TWELVETH_ROOT;
		printf("%f\n");
	}
}

Expression: combination of opertors and operands
- Expression has a value
- Statements:
  - Simple statement
    - Declaration
    - Assignment
    - Function call
    - Structured statement (e.g. while (1) i = 1;)
    - NULL statement
  - Compound statement (Block)
Fundemntal operators (=, +, -, -(unary), *, /)
Precedence (left-to-right, (), unary +-, */, +-, =)
```
 e.g. 24 / 2 * (1 + 9 / 3) 
```

Modulus operator %

#include <stdio.h>
#define SEC_PER_MIN 60

void main(void)
{
	int sec, min, left;
	printf("Enter seconds: ");
	scanf("%d", &sec);
	min = sec / SEC_PER_MIN;
	left = sec % SEC_PER_MIN;
	printf("%d seconds is %d minutes and %d seconds.\n", sec, min, left);
}

Increment and descrement operators: ++ and -- (prefix & postfix)

num = 5;
printf("%d %d\n", num++, num * num++);
ans = num + num++;
ans = num+++num;
ans = num+++++num;

Type conversions

char and short promoted to int
type of a value is changed to the type of the assigned variable
in demotion, there may be loss of data

if mixed, smaller types are promoted to larger types

#include <stdio.h>
#define SEC_PRE_MIN 60
void main(void)
{
	char ch;
	int i;
	float fl;
	
	fl = i = ch = 'Q';
	printf("ch = %c, i = %d, fl = %2.2f\n", ch, i, fl);
	ch++;
	i = fl + 2 * ch;
	fl = 2.0 * ch + i;
	printf("ch = %c, i = %d, fl = %2.2f\n", ch, i, fl);
}

Cast operator
```
 Function with arguments
```

Assignment #4: Due October 8, 1996.

p.158: #1, 2, 3, 6; p.202: #1

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