L2 - Arrays

Question 1

clang

Answer 1

Compiler we’re using when we run the program make/ code

Question 2

How do you link libraries with a command line argument when compiling with clang?

Answer 2

-l
clang -o hello hello.c -lcs50
This links and renames the file

Question 3

What are the four steps to turn source code into binary?

Answer 3

1. pre-processing
2. compiling
3. assembling
4. linking

Question 4

Pre-Processing

Answer 4

Converts the included libraries (#include <stdio.h>) and adds the prototypes to the top of the file to be able to use all functions in that .h file</stdio.h>

Question 5

Compiling

Answer 5

Convert source code to assembly code.

Question 6

Assembling

Answer 6

Takes assembly code and converts to 0/1s

Question 7

Linking

Answer 7

Pulls all 0/1s in all of the files together.

Question 8

Debugging

Answer 8

Running through code to figure out issues.

Question 9

Break point.

Answer 9

Point to pause execution of code, which is by adding a dot in the gutter. It stops at the first line of executable code, on or right after the breakpoint. The highlighted code has not been run yet.

Question 10

Garbage values

Answer 10

Values that are present before variables are set.

Question 11

Step over

Answer 11

Execute but don’t get into full detail.

Question 12

Step in

Answer 12

Walkthrough the function step by step in detail

Question 13

Step out

Answer 13

Pulls you out of the step by step detailed function to execute without full details.

Question 14

Arrays

Answer 14

Sequence of values stored in memory without any gaps in between them with a 0 index, so position 1 is 0.

Question 15

What is this?
int scores [3];

Answer 15

declaration of an integer array called “scores”, with a length of 3

Question 16

Initialize an array

Answer 16

int scores [3];
Data type. Name. Array size.

Question 17

assign a value to an int array

Answer 17

score[0]=72;
This cerates an int array and assigns 72 to index 0 (first position) of the array

Question 18

constant

Answer 18

const Variable
This prevents the variable from being changed during the execution of the program and should start with a capital letter.

Question 19

What is the prototype for a function that takes in an integer value and an array?

Answer 19

int average(int length , int array[]);

Question 20

What is special about chars/ints?

Answer 20

chars can return the int numeric value, and ints can return the char letter/symbol values

Question 21

Length of a string

Answer 21

N+1
(Length+1)

Question 22

NUL or /0

Answer 22

byte with all zero bits (00000000) which indicates the end of a string, so the length of the string is always it’s length+1
NUL is not the same as NULL

Question 23

How to use command line arguments to get input from a user with your main function

Answer 23

int main (int argc, string argv[])
Pronounced arg c and arg v

Question 24

what is argc in main function?

Answer 24

Argument count:
The number of words the user typed in the command line prompt to run the program
ex: ./hello Bianca
argc = 2 since the filename is always the string in argc

Question 25

what is argv in main function?

Answer 25

Argument vector array:
Takes the data entered when running the program and stores it into an array starting with the filename as index 0

Question 26

exit status

Answer 26

The value returned when a program finishes running. A zero always means the program ran successfully and exited correctly. Any other value means an error occurred.

Question 27

return 0;

Answer 27

Can be used to exit a program

Question 28

echo $?

Answer 28

Can be used as a command line prompt to see the most recently executed program’s exit code.

Question 29

Cryptography

Answer 29

Scrambling data that needs to be unlocked with a key to figure out the message

Question 30

initialize an int array with the values 1,3,2,4,2

Answer 30

int numbers[5]={1,3,2,4,2};
data type.name. square brackets. size. =. curly braces. comma separated numbers. semicolon