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### Chapter 5

2. [was #2]

(a) `1`
(b) `1`
(c) `1`
(d) `1`

4. [was #4] `(i > j) - (i < j)`

6. [was #12] Yes, the statement is legal. When `n` is equal to 5, it does nothing, since 5 is not equal to –9.

10. [was #16] The output is

```onetwo
```

since there are no `break` statements after the cases.

#### Answers to Selected Programming Projects

2. [was #6]

```#include <stdio.h>

int main(void)
{
int hours, minutes;

printf("Enter a 24-hour time: ");
scanf("%d:%d", &hours, &minutes);

printf("Equivalent 12-hour time: ");
if (hours == 0)
printf("12:%.2d AM\n", minutes);
else if (hours < 12)
printf("%d:%.2d AM\n", hours, minutes);
else if (hours == 12)
printf("%d:%.2d PM\n", hours, minutes);
else
printf("%d:%.2d PM\n", hours - 12, minutes);

return 0;
}
```

4. [was #8; modified]

```#include <stdio.h>

int main(void)
{
int speed;

printf("Enter a wind speed in knots: ");
scanf("%d", &speed);

if (speed < 1)
printf("Calm\n");
else if (speed <= 3)
printf("Light air\n");
else if (speed <= 27)
printf("Breeze\n");
else if (speed <= 47)
printf("Gale\n");
else if (speed <= 63)
printf("Storm\n");
else
printf("Hurricane\n");

return 0;
}
```

6. [was #10]

```#include <stdio.h>

int main(void)
{
int check_digit, d, i1, i2, i3, i4, i5, j1, j2, j3, j4, j5,
first_sum, second_sum, total;

printf("Enter the first (single) digit: ");
scanf("%1d", &d);
printf("Enter first group of five digits: ");
scanf("%1d%1d%1d%1d%1d", &i1, &i2, &i3, &i4, &i5);
printf("Enter second group of five digits: ");
scanf("%1d%1d%1d%1d%1d", &j1, &j2, &j3, &j4, &j5);
printf("Enter the last (single) digit: ");
scanf("%1d", &check_digit);

first_sum = d + i2 + i4 + j1 + j3 + j5;
second_sum = i1 + i3 + i5 + j2 + j4;
total = 3 * first_sum + second_sum;

if (check_digit == 9 - ((total - 1) % 10))
printf("VALID\n");
else
printf("NOT VALID\n");

return 0;
}
```

10. [was #14]

```#include <stdio.h>

int main(void)
{

return 0;
}

case 10:
break;
break;
break;
break;
case 5:
case 4:
case 3:
case 2:
case 1:
break;
}

return 0;
}
```