notes/education/software development/ECE1400/Chapter 5 Exercises.md

2. The following program fragments illustrate the logical operators. Show the output produced by each, assuming that i, j, and k are int variables.

a. i = 10; j = 5;

printf("%d", !i < j);

// Expected output: `1`, because `!i` evaluates to 0, and 0 is less than 5, so that expression evaluates to true, or 1.

b. i = 2; j = 1;

printf("%d", !!i + !j);

// Expected output: `1`, because !!2 evaluates to 1, and !j evaluates to 0

c. i = 5; j = 0; k = -5;

printf("%d", i && j || k);

// Expected output: `1`, because i && j should evaluate to 0, but `0 || 1` should evalulate to true.

d. i = 1; j = 2; k = 3;

printf("%d", i < j || k);

// Expected output: `1`

4. Write a single expression whose value is either -1, 0, or 1 depending on whether i is less than, equal to, or greater than j, respectively.

/*
	If i < j, the output should be -1.
	If i == j, the output should be zero
	If i > j, the output should be 1.
*/
(i > j) - (i < j)

6. Is the following if statement legal?

if (n == 1-10)
	printf("n is between 1 and 10\n");

Yes the statement is legal, but it does not produce the intended effect. It would not produce an output when n = 5, because 1-10 evaluates to -9, and -9 != 5.

10. What output does the following program fragment produce? (Assume that i is an integer variable.)

int i = 1;
switch (i % 3) {
	case 0: printf("zero");
	case 1: printf("one");
	case 2: printf("two");
}

The program would print onetwo because each case is missing a break statement.

11. The following table shows the telephone area codes in the state of Georgia along with the largest city in each area:

Area code	Major city
229	Albany
404	Atlanta
470	Atlanta
478	Macon
678	Atlanta
706	Columbus
762	Columbus
770	Atlanta
912	Savannah

Write a switch statement whose controlling expression is the variable area_code. If the value of area_code is not in the table, the switch statement will print the corresponding city name. Otherwise, the switch statement will display the message "Area code not recognized." Use the techniques discussed in section 5.3 to make the switch as simple as possible.

int area_code;

switch (area_code) {
	case 404:
	case 470:
	case 678:
	case 770:
		printf("Atlanta");
		break;
	case 706:
	case 762:
		printf("Columbus");
		break;
	case 229:
		printf("Albany");
		break;
	case 478:
		printf("Macon");
		break;
	case 912:
		printf("Savannah");
		break;
	default:
		printf("Area code not recognized.");
		break;
}