Chapter 2 Questions

Question 1

What is the meaning of the #include statement?

Answer 1

it tells the compiler what libraries need to be linked

Question 2

What is the difference in a library (.h) that is between <> verses between “”?

Answer 2

<> is a prewritten library
“” is a user defined library

Question 3

What is the library stdio.h for?

Answer 3

contains standard input and output functions such as scanf and printf

Question 4

What is the library math.h for?

Answer 4

contains mathematical functions such as sqrt and pow

Question 5

What are the four (4) valid options to define the main() function in C?

Answer 5

main(){…}
void main(){…}
int main(){… return 0;}
main(int argc, char *argv[]){…}

Question 6

When you have a main() function defined with a type int, what does the statement “return 0;” mean?

Answer 6

the program ran as expected/ no errors or exceptions

Question 7

In the statement “scanf(%d, &i)”, why do we use “&” in the second parameter?

Answer 7

to store the scanned value at the address?

Question 8

What is the purpose of the %d, %f, %c, %s, and %p in the printf() function?

Answer 8

they are

Question 9

What are the two (2) types of variables, scope-wise, that we have in C?

Answer 9

local and global

Question 10

If C does not have boolean type variables, how are relational operations (needed in conditions and loops) handled?

Answer 10

if it returns a 0 it is false, if it returns any other number it is true

Question 11

How many basic data types are there in C?

Answer 11

5 (int, double, float, char, void)

Question 12

How is the scope of a variable defined in C?

Answer 12

it starts at the declaration and goes until the end of the block defined by {}

Question 13

When declaring a variable/function in C, what does the rule “declaration-before-use” mean?

Answer 13

you cannot use a variable ahead of where it is declared (scope)

Question 14

What is a forward declaration and why do we want to use it?

Question 15

What are long, short, signed, and unsigned?

Answer 15

modifiers

Question 16

What is the initial default value of an integer variable when it is defined as int x?

Question 17

What is the initial default value of an character variable when it is defined as char a?

Question 18

What is the initial default value of an float variable when it is defined as float x?

Question 19

C does not have a byte data type, is there an equivalent type for it?

Answer 19

yes, char

Question 20

What is the issue with trying to define an array as int a[] or char []?

Answer 20

the length of the array isn’t given so memory cannot be allocated?

Question 21

What is the function of the null character (‘\0’) when working with strings in C?

Answer 21

it represents the end of the string

Question 22

While working with strings in C, if we have char s1[3], s2[]; can we do s1 = s2? Yes or no and why?

Question 23

How would you describe a pointer in terms of what is stored in them?

Answer 23

a pointer stores an address

Question 24

How would you describe a pointer in terms of the type of memory they use?

Question 25

Is it possible to have pointers to any type in C?

Answer 25

yes

Question 26

What is the result of combining these two operands?

(&y)
&(y)

Question 27

There are two operators for pointers, * and &. What is the purpose of each of them?

Answer 27

• returns the value stored in the variable to which the attached variable points to
  & returns the address of the variable to which it is attached

Question 28

Why is it said that an array can be seen as a pointer? Justify in terms of the information stored in the pointer and array.

Question 29

In C, there is no string type, however, there are ways to implement strings? What are they?

Answer 29

an array of char

Question 30

While defining a pointer to a character and initializing it with a string literal, it is said that the string is immutable. What does that mean and would the pointer also be immutable?

char *str = “Hello World”;

Answer 30

when a string is immutable, it cannot be changed during runtime, with the exception of using pointers

no the pointer would be mutable in this example

Question 31

Given the following definition of an array, give the same array using pointers.

int array[] = {1, 2, 3, 4, 5};

Provide a visual representation of the above array and pointers.

Answer 31

*(array + 0) = 1;
*(array + 1) = 2;
*(array + 2) = 3;
*(array + 3) = 4;
*(array + 4) = 5;