Starting

Question 1

What are some of the differences between Java and C?

Answer 1

Java:

• Object Oriented
• I/O, layered IO
• Macros are rarely used
• Classes for namespaces

C;

• Function oriented
• Byte stream I/O
• Macros are common
• Single name space, file oriented

Question 2

Some more differences between C and java?

Answer 2

Java:

• Manages the length of the array
• Garbage collector manages the allocation and the freeing of memory

C:

• You need to manage the length of the array on your own
• Memory that is created on the stack is manged automatically but that which is allocated on the heap is upto the programmer to manage and free

Question 3

Which are the 2 compilers used for C?

Answer 3

gcc and clang

Question 4

How to compile a file world.c in both gcc and clang?

Answer 4

gcc world.c -std =c90

clang world,c -std=c99

Question 5

what are the different compiler options and what are their uses?

Answer 5

The different compiler options are

• -o: Name your executable
• -g: Add in debugging information
• -Wall: Give warnings
• -Wextra: Give additional warnings
• -O, O2, O3: Compiler optimization and different levels of it.

Question 6

What are the 2 stage compilation for gcc?

Answer 6

Compilation using the -c flag

Linking using the -o flag

Question 7

What is the size of char and is it implementation dependent?

Answer 7

The size of char on any computer will be 8

Question 8

What is the range of signed and unsigned chars

Answer 8

Unsigned chars: {0…255}

Signed chars: {-128….127}

Question 9

What is the order of the size of the types?

Which all data types are signed/unsigned by default?

Answer 9

The order is as follows

char < short < int < long < long long

Every type is signed by default except for chars

Question 10

What variables are initialized to 0.

Answer 10

Only global variables are initialized to 0

Question 11

What are print modifiers for float, shortest of %f,%e

Answer 11

float: %f

shortest of %f, %e: %g

Question 12

Print modifiers for hex, octal, long int and double

Answer 12

Hex: %x,

Octal: %o

long int: %li

double: %lf

Question 14

What to watch out for when using the print function:

Answer 14

The compilers don’t check to see if the number of type modifiers is equal to the number of arguments to be output.

Question 15

Precedence of operators

Answer 15

• Assignment is the lowest
• * / % are all equal
• relational operators > == and !=
• ++–(cast) this is evaluated from left to right
• addition and subtraction > relational operators

Question 16

What is #include

How to include a library header file?

Answer 16

include <curl></curl>

it is preprocessor directive. These are used to insert header files into the program. These header files are given the extension .h

Question 17

What is the scanf function?

Answer 17

The scanf function is used to read in input. It only contains conversion specifications

Question 18

What are the things to watch out for when using scanf?

Answer 18

• The programmer must make sure that the number of input specifiers matches the number of arguments
• The & symbol precedes the name of the variable and the programmer must make sure that this is included.
• Scanf also peeks at the final new line without reading it

Question 19

Outline how scanf works

Answer 19

1. Scanf reads the input by matching the input specifiers with the input data given to it.
2. it skips white spaces if necessary
3. It reads the input until there is a mismatch in the input specifiers
4. If everything is fine with one specifier then it moves onto the next specifier, eventually reading the whole line if nothing goes wrong.

Question 21

What are the modifers that can be used interchangeably in scanf?

Answer 21

The modifiers that can be used interchangeable are %e. %f, %g