Computer Programming in C Chapter 6

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Computer Programming Chapter 6 2

6 장 . Structure

목차1. Structure 기본 개념2. Typedef3. Pointer to Structure4. Structure Array5. Structure 를 이용한 Function Parameter6. Union7. Bitwise Structure

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1. Structure 의 기본 개념

복합적인 데이터 Example:

StudentScore, StudentName, StudentYear…

Structure 의 이용struct student { int score; int year; char name[50];};

struct student students[100];

int studentScore[100];int studentYear[100];char *studentName[100]

students[i].score=40;students[i].year=4;strcpy(student[i].name,”Lik”);

structure 의 member 표지

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2. Typedef

Typedef User-Defined Type : cf. Built-in Type

More convenient than struct

struct student { int score; int year; char name[50];};

struct student students[100];

typedef struct { int score; int year; char name[50];} student;

student students[100];

New type

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3. Pointer to Structures

Pointer to Structures Structure Types 의 변수가 저장된 주소

typedef struct { int score; int year; char name[50];} student;

student *pstudent;

pstudent=malloc(10*sizeof(student));for(i=0;i<10;i++) { pstudent->year=0; pstudent->score=0; pstudents++;}

structure 의 member 표시

student students[100]; pstudent=students;for(i=0;i<10;i++) { pstudent->year=0; pstudent->score=0; pstudents++; }

student students[100]; pstudent=students;for(i=0;i<10;i++) { pstudent[i].year=0; pstudent[i].score=0; }

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4. Structure Array

다른 Type 과 같이 Array 가능

struct student { int score; int year; char name[50];};

struct student students[3];

typedef struct { int score; int year; char name[50];} student;

student students[]= { {3.0, 1, “WG-1”}, {3.5, 1, “WG-2”}, {2.9, 1, “WB-1”}};

for(i=0i<3;i++){ students[i].year=0; students[i].score=0.0;}

student *pstud;

pstud=students;for(i=0i<3;i++){ pstud->year=0; pstud->score=0.0; pstud++;}

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5. Struct 와 Function Parame-ter Structure 를 이용한 Function 의 Param-

eter 매우 단순

typedef 는 가능한 header file 에 정의

Structure Pointer 를 이용한 Function Parameter

float Vector10Norm(float v1, float v2, float v3, …, v10)

float Vector10Norm(struct vector10 vector)

inputStudent(student &stud); void inputStudent(student *s) { s->year=3; s->score=3.56; strcpy(s->name,”WG-2”);}

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6. Union

경우에 따라 다른 Type 을 가지는 것의 Wrapping

Sizeof(Union): 가장 큰 size 에 의하여 결정

typedef struct { char name[50]; int age; char status; /* 0: student, 1: prof. */ union { unsigned int year; /* for student */ char position[20]; /* for professor */ } level;} UnivPerson;

UnivPerson a;a.status=0; s.level.year=0;

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7. Bitwise Operation

Bit 단위로 변수를 사용 Structure Type 을 이용

typedef struct { unsigned short year:2; /* 00:1, 01:2, 10:3, 11:4 */ unsigned short gender:1; /* 1: female, 0: male */ unsigned short dept:5; /* 000: phy, 001: chem ... */} studentStatus;

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Mask 이용#define Mask_Year 0x0003 /* 0000 0000 0000 0011 */#define Mask_Gender 0x0004 /* 0000 0000 0000 0100 */#define Mask_Dept 0x0038 /* 0000 0000 0011 1000 */

#define Male 0x0000#define Female 0x0004

unsigned short studentStatus;studentStatus = (studentStatus & ~Mask_Gender) | Male;. . .

if (studentStatus & MaskGender == Male) ...