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240-120 Introduction to Computer Programming

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1

2 Introduction to C Language Programming

1.

1.

1.1 1.2

1.3

1.4

1.5 1.6

1.7 1.8

1.9

1.10

2.

2.1

2.2 ASCII

2.3

2.4 2.5

3.

3.1

3.2 3.3

3.4 3.5

3.6 -3.7

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1. (Introduction to basic C language)

240-120 Introduction to ComputerProgramming

1.1

(Function)(Procedure) 1 main

main

main ( )

{ printf ( My house) ;

printf (is very beautiful);

triangle( );

box( );

prinf(finish) ;

}

triangle( ) triangle{ /* draw triangle */

}

box ( ) box{ /* draw box */

}

1.1

printf ..

printf..

triangle

box

printf.

triangle

box

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main main

1.2 2

main 2

1.2.1 (Heading)

( )

int main(char) main char int

1.2.2 (Compound Statements) 3

(Variable Declaration)

(Statement) ;

{ }

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(Heading){ (Variable Declarations)

(Statements)

}

1.3

1. (Source file) .c .cpp (Editor)

( )

2. (C Compiler) (Object file) .obj ( )

3. (Linker)

(C Library) .exe ( )

1.2

1.

Source file

C Compiler

ComputerObject fileComputer Execute file

Linker Library

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#i ncl ude

voi d mai n( voi d){

pr i nt f ( Hel l o Wor l d) ;}

1.c2.

1.obj3.

stdio.h ( #include ) 1.exe** printf printf stdio.h

stdio.h printf

1.4 3

1.4.1

.h1.4.2 1.4.3

2.2

#i ncl ude

char a;

i nt mai n( voi d){

a = 23;

pr i nt f ( Hel l o Wor l d) ;r et ur n a;

}

1.3

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Hello World

- #include stdio.h - main main

- char a a - a = 23 a 23

- printf(Hello World) printf

** (C Statement) ;

1.5 1. printf , scanf , for2. ; printf(Hello) ;3. (Free Format)

printf(Hello); printf(Goodbye); a = 95;

1 1

1.6 (Comment)

/* */

/* ..*/

/*

. .

..*/

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1.7 2

1.7.1 (Keywords) auto default float register struct volatile break

do far return switch while case double

goto short typedef char else if signed

union const enum int sizeof unsigned continue

extern long static void

1.7.2 (User Defines words)

test Test

_

_

** Borland C 32

1.8 (Variable)

char, int, long, float, double, unsigned int, unsigned long int,

2 1. Global Variable

0 ()

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2. Local Variable

, , ,.....;

1. char 1

1 A , b , 1 , ?2. integer

-32768 32767 2 5 -10 25343. long 2

( long int )4. float a.b x 10e

4 3.4E-38 3.4E+38 6 10.625 -6.67

5.

double

float

2 8 1.7E-308 1.7E+3086. unsigned

() unsigned int

Char 8 ASCII character (-128 127)Unsigned char 8 0-255

Int 16 -32768 32767long int 32 -2147483648 2147483649Float 32 3.4E-38 3.4E+38 6 Double 64 1.7E-308 1.7E+308 12 Unsigned int 16 0 65535Unsigned long int 32 0 4294967296

1.1

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11. #i ncl ude2. #def i ne PI 3. 141593. i nt ar ea; / * gl obal var i abl e */

4. mai n( ) 5. { f l oat r adi us; / * l ocal var i abl e * / 6. f l oat pr ocess( ) / * f uncti on decl ar at i on */ 7. pr i nt f ( Radi us = ?) ; scanf ( %f , r adi us) ; 8. pr ocess( ) ; 9. pr i nt f ( Ar ea = %f , ar ea) ; 10. pr i nt f ( %f , r adi us) ;

}

11. f l oat pr ocess( ) 12. { f l oat r adi us; / * l ocal var i abl e */ 13 pr i nt f ( Radi us=?) ; scanf ( %f , r adi us) ; 14 ar ea=PI *r adi us*r adi us; 15 pr i nt f ( Ar ea = %f , ar ea) ; 16 pr i nt f ( %f , r adi us) ;

}

2 i nt a ;

a -35768 32767

3 i nt num1=8; num1 8

4 f l oat money, pr i ce ; money price 6

5 char ch= A ch 1 A

6 unsi gned l ong i nt t est ;

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test

char a,b,c,d; /* a,b,c,d character */unsigned e; /* e unsigned int */

char key = A; /* key character A*/

char name = SAM /* name character SAM */

1.9 (Preprocessor)

#

#include #define #if #program

#endif #error #ifndef #undef

#elif #else #ifdef

2

1.9.1. #include

#include #include filename

#include dos.h

#include sample.h sample.h

* Option directory

* (Header Files) .h

1 stdio.h printf

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main() process clrscr() conio.h include conio.h

1.9.2 #define

#define ()

#define TEN 10 TEN 10#define PI 3.141592654 PI 3.141592654

constant 3

1 2 3 ( ASCII)

1

255 decimal int 0xFF hexadecimal int 0377 octal int 255L 255l long int 255U 255u unsigned int 0xFFUL unsigned long

int

15.75E2 floating point -1.23 floating point .123 floating point 123F floating point

a character

string ,

1.2

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1.10 (Statement and Expression)

, (Statement)

; {} (Statement)

(Operands) (Operators) 3 * 2 - 1 + 7 a * 5

7 + 5 a + b

( a * 3 ) + 5 2.0 * sin(2.12)

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2. (Input and Output)

2.1

2.2 (ASCII) American Standard Code for

Information Interchange 128 128

Extended ASCII code - .

(Characters) Character

A A

4 4

b b

\0 0

\x7 7

(String)

(Double

qoute) Hello World! Hello World!

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2.3

printf

printf ( control , argument list ) ;

2 control

control 2

printf ( sum of x = );

sum of x =

(Format Code)

%

%d int %ld long int long%u unsigned int unsigned%c char %s string %o int (octal) %x int (hexa) %f float %e float, double %lf double double

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2.1 printf argument list

argument list

1 ( , )* argument list Control Control Argument list

** (Format Code)

Escape Sequence \ (Back-Slash) 1

Escape Sequence

\a 0x07 \b 0x08 cursor \f 0x0c \n 0x0a \r 0x0d cursor \t 0x09 tab \v 0x0b tab

\\ 0x5c \\ 0x2c

\ 0x22 \? 0x3f ?

2.2 Escape Sequence

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1 printf

#i ncl udemai n( ){ i nt sum=5; f l oat e=11. 55;

pr i nt f ( Thi s i s t he t est Pr ogr am. ) ;pr i nt f ( The r esul t i s %d \ n, sum) ;pr i nt f ( The r esul t i s %f %e , e, e) ;

}

Thi s i s t he t est Pr ogram. The r esul t i s 5The r esul t i s 11. 550000 1. 155000e+01

2 printf

#i ncl udemai n( ){ char a= A ;

char name=Ar ee;i nt x, y;

pr i nt f ( What i s the f i r st char acter \ n);pr i nt f ( The f i r st char acter i s %c \ n\ n, a) ;x=10; y=15;pr i nt f ( x+y= %d \ n, x+y) ;

pr i nt f ( %d 5 = %d \ n, y, y- 5) ;x=65;pr i nt f ( x i s %c, x) ;

pr i nt f ( Thi s progr am r un by %s, name) ;}

What i s t he f i r st char act erThe f i r st char act er i s A

x+y=2515- 5=10x i s 65 Thi s pr ogr am r un by Ar ee

(field) + -

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3 printf

#i ncl ude voi d mai n( ){

pr i nt f ( | 1234567890| \ n) ;pr i nt f ( | %10s| \ n, pr i ce) ;

} price 10

% 3

| 1234567890|| pr i ce|

price 10 - printf() 3

pr i nt f ( | %- 10s| \ n, pr i ce) ;

| 1234567890|| pr i ce |

float a.b a b 6 printf() 4

pr i nt f ( | %10. 3f | \ n, 1999. 95) ;

6

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| 1234567890|| _ _1999. 950|

1999.95 10 3

int string

7 printf() 4

pr i nt f ( | %. 10s| \ n, Thi s program i s r unni ng) ;

pr i nt f ( | %. 10d| \ n, 20) ;

7

| 1234567890|| Thi s pr ogr || 0000000020|

2.4

scanf

scanf ( control , argument list );

control control

printf** control scanf

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argument list argument list

( , )

scanf & (string) ** scanf argument list 1 scanf

char a; int b;

char name[22]; /* name 22 21 \0 22 */

scanf(%c %d,&a,&b); /* scan char a scan int b */

scanf(%s,name); /* scan string name */

2 scanf integer x1

30 letter

#i ncl udemai n( ){ i nt x1;

char l et t er [ 30] ;scanf ( %d, &x1) ;scanf ( %s, l et t er ) ;

}

2.5 2.5.1

getchar ( )

getchar ( ) 1 enter

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getchar ( ) ;

#i ncl udemai n ( ){ char ch;

ch=getchar ( ) ;}

1 ch enter

2.5.2 getch ( )getch ( ) 1

enter

getch ( ) ;

#i ncl ude mai n ( ){ char x;

x = get ch( ) ;}

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1 x enter

2.5.3 gets ( )gets ( ) ()

( gets = get string)

gets ( n ) ;

n \0 enter

#i ncl ude mai n( ){ char name[10] ;

gets( name) ;}

name 10 name 9 name 10 () \0

2.5.4 putchar( )

putchar( ) 1

putchar ( ) ;

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#i ncl ude

mai n ( ){ char x;

x=get ch ( ) ;pr i nt f ( Her e i s t he out put \ n) ;put char ( x ) ;

}

A

Here i s t he out putA

2.5.5 puts ( )puts ( )

puts ( n ) ;

n

#i ncl ude mai n ( ){ char name [ 10] ;

get s ( name) ;put s ( name) ;

}

name

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C (Precedence)3.2

( ) - * -

* / + - * -

3.2 Precedence

a + b* c C % * / + - a+b+c a b c

%

/

a / b

a b integer integera b float float

39 / 5 739. / 5 7.8

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integer floating operand

1/3( 0) 1.0/3.0 0.333 1.0/3.0 1.0/3 1/3.0 0 (Increment & Decrement)

- ++ - --

2 - (prefix) ++n- (postfix) n++

1 n ++n n++ ()++n n++

n 5

x = n++; x 5x = ++n; x 6

(i+j)++

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3.2 (Relational, Equality, and Logical Operators)

Operator < (Relational Operator) >

=

== (Equality Operator) !=

! (Logical Operator) &&

||

3.3 3.2.1 (Relational Operator)

2 int 1 0 (0 )

4

< () > () = ( )

ab /* a=10 b=8 1 () */-1 >= (2.2*X+3.3)

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**

1 !a /* a */!(x+7.7)

!(a

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&& ()

2 3.4

P Q P && Q

0 0 0

0 1 0

1 0 0

1 1 1

3.4 && P Q

|| ()

2 3.5

P Q P || Q

0 0 0

0 1 1

1 0 1

1 1 1

3.5 || P Q

! ()

3.6

P !P

0 1

1 0

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3.6 ! P

3.3

(Compound Operator)

+ 10

+= -= /= %=

= |= ^=

i = i + 1; i += 1;

i = I a; i - = a;i = 1 * (a + 1); i = *=a+1;i = i / (a-b); i /= a-b;i = i %101; i %= 101;i = i >= i;i = i & 01; i |= 0xf;i = i & 01; i | = 0xf;i = i ^ (07 | 0xb); i ^ = 07 | 0xb;

3.4. (Sizeof Operator)

Variable op= expression;

Variable = variable op expression;

Sizeof sizeof ()

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i nt ABC;

pr i nt f ( %d, si zeof ( ABC) ) ;

2

ABC integer 2 integer

3.5. (Conditional Operator)

? (Condition Expressions) 1 ? 2 : 3

1 0 () 2 1 0 3

c = ((a+5)? (a+1) : 0);

a 1 a+5 c 2 a+1 a 5 a+5 c 0

#i ncl udevoi d mai n( voi d)

{ i nt a, b;a = 15;b = ( ( a+5) ? ( a+1) : 0) ;pr i nt ( b= %d\ n, b) ;a=0;

b=( ( a+5) ?( a+1) : 0) ;pr i nt f ( b= %d\ n, b) ;a=5;b=( ( a+5) ?( a+1) : 0) ;pr i nt f ( b= %d\ n, b) ;

}

b = 16

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b = 1b = 0

3.6 -

- 3.7

(), [], ->, |, ~, ++, --, +(), -(), *, &(type), sizeof *, /, % +, - ()

= ==, != & ^ | && || ? : =, +=, -=, /=, %=, &=, ^=, |=, = ,

3.7

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3.7 (Casting) int int

(int)(a*5.2) output int

(float)(b+5) output float

()

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240-120 Introduction to Computer Programming34

C

a.ba

ab

+ d.

ab

ba

+

b.2

c

ba+ e.

2

+

dc

ba

c.

c

ba

cb

a

+

f.abc

cba

acbcab

++

++

a, b, c, d integer 4 float

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