Memory Analysis in C language

C Memory Analysis in the language

One, the binary

we need to know. 4 medium: Binary, octal, decimal, hexadecimal

#include <stdio.h>

int main ()

{

         // By default is the decimal

Intnumber = 12;

         // Binary

intnumber2=0b1100;

         // octal

Intnumber3 = 014;

         // hexadecimal

Intnumber = 0xc;

Return0;

}

Printf types that are output in a different binary form:

%d usually outputs an integer in decimal

%o usually outputs an integer in octal

%x usually outputs an integer in hexadecimal

%u output integers as unsigned decimal

%c Output one character

%s output one or more strings

%f outputs a single-double-degree value in decimal form, by default 6 bit

%e shift the standard exponential form output single double precision number, the number of small water level is 6 bit

Any data in memory is in binary form!

an int type of data occupies 4 bytes,32bit

For example:

Int number=12 ;

shown in memory as:

0000 0000 0000 0000 0000 0000 0000 1100

N bit binary Value range:

2 value range of bit bits: 0~3

3 value range of bit bits: 0~7

N range of values for bits: 2n-1

Test an integer with the binary output code:

Void putbinary (INTN)

{

Int bits = sizeof (n) *8-1;

while (bite>=0) {

Printf ("%d", n>>bit&1);

If (bits%4==0)

Printf ("");

}

Printf ("\ n");

}

Second, range of values for data types:

Char-----1 of bytes ---8bit--- range of values: -27~27-1

Int-------4 of bytes ---32bit--- range of values: -231-231-1

Float----4 of bytes ----32bit--- range of values: 3.4e-38~3.4e38| | -3.4e38~-3.4e-38

Double---8 of bytes ---64bit- range of values: 1.7e-308~1.7e308| | -1.7e308~1.7e-308 Three , type descriptor:

Int--------4 of bytes -----------%d

Short --------4 of bytes -----------%d

Long--------8 of bytes -----------%ld

Long Long----8 of bytes -------%lld

signed signed: Positive, 0 , Negative

unsigned unsigned: Contains 0 , Positive

signed with the unsigned The difference: signed The highest position should be regarded as the sign bit; unsigned The highest bit is not used as a sign bit.

Four, bit arithmetic

1. & bitwise and

For example:

9&5 ;

converting data into binary and arithmetic

2. | bitwise OR

For example:

9|5 ;

convert data into binary or arithmetic

3. ^ bitwise XOR: As long as two binary bits are not equal to 1 in place 0

For example:

9^5 ;

convert data into binary for XOR operation

n^n result is 0 ;

Any value that is 0 different or gets the original value

4. ~ bitwise to reverse

For example:

to ;

9 all the bits are reversed;

5.<< Move left

Move the bits of an integer all the way to the left N -bit high discard the low fill 0

6. >> Move Right

Move the bits of an integer all the way to the right N bits to keep the sign bit constant

Five, Char

// single quote ' ' can only enclose single-byte characters

//char c= ' male ' This is the wrong wording .

//char c = "A"; This is the wrong wording .

//char c = A; This is also the wrong wording.

Char can be used as an integer, its value range is: -128~127 ;

Escape characters:

\ n line Break ASCII the value is Ten

\ t Skip to Next Tab location ASCII the value is 9

\\              represents a backslash character ASCII the value is the

\ ' represents a single quote character ASCII the value is the

Converts the case of a letter

Uppercase Upper

lowercase Lowwer

Char Upper (char c)

{

If (c>= ' a ' &&c<= ' Z ')

return c-32;

ElseIf

return C;

}

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Memory Analysis in C language