ics 45c: mini test 1

compare floating data types

• float < double < long double

• NO UNSIGNED

compare int data types

• short int < int < long int/size_t

• YES UNSIGNED

conditional

if (var < 10)

{

// do smth
}

else

{

// do smth

}

loop

for (int = 0; i < 5; i++)

{

// do smth;

}

arrays

• fixed length list of elements of SAME data types stored in CONSECUTIVE memory

• diff data types require diff lengths of memory, might not fit

• size determined at compile time, NEVER CHANGES

• make sure to initialize it, or else computer will assign smth random

• int array[5];

• char array[] = {‘a’, ‘b’, ‘c’}

malloc()

• memory allocate

• REQUESTS: a chunk of memory on the STACK/HEAP

• ARGS: # of bytes

  • use sizeof(datatype)

• RETURNS: address of 1st byte in chunk, void pointer

  • void *address = malloc(4);

  • NEEDS to be converted to pointer of 0desired type to use

  • if u want int, then int int_address = (int *) malloc(sizeof(int))

    • this var holds mem address that points to an INT

calloc()

• same as malloc(), but useful for arrays

• 0’S OUT ALL BITS IN THAT MEM LOCATION

• void *calloc(size t num, size_t size)

  • num of elements, size of each element

std::cout

• character out, sending characters to console (like printf)

• DONT HAVE TO SPECIFY DATATYPE

• default aligntment - std::left

• std::cout « var;

std::cin

• like scanf, input (reads in from console)

• std::cin » var;

memset

• memory set

• sets each byte in range of mem to a SPECIFIC VALUE

• void *memset(size_t dest, int ch, size_t count)

  • dest address to set mem at

  • value to set mem to

  • num of bytes to set

• int *ptr = (int*)malloc(10*sizeof(int));
  memset(ptr, 01, 10*sizeof(int));

  • sets every byte to 0xFF

include <smth>

• looks at specific FOLDER on computer

• for things u use frequently

• ex: <stdio.h>

include “smth”

• for UR files

• look where ur currently located

header files

# ifndef FILENAME_HPP

# define FILENAME_HPP

void func1();

void func2();

# endif

header guards

main.cpp:

# include “physics.hpp”

# include “physics.hpp”

dereference pointer

• after requesting memory & creating pointer, how to access the acc value at that address

• STAR BEFORE THE POINTER

• printf(“%d”, *ptr)

• c = *p

initialize pointer

int num; // initialize the var

int *num_ptr; // initillize the ptr to the var, allocates space, but nothing pointed to rn

num = 42;

num_ptr = &num; // create ref to num and store it in num_ptr, now points to num.