c语言程序设计课件ppt（英文）c program language 之7 structure

Structure Xue Qing2009.4 Structure What is StructureDefinitionInitializationAccess the members of structureStructure and pointerStructure and functionStructure and arraynumber, name , score1, score2, score3, score4 What is StructureIn order to deal with the special data which has several member with different data type, it is need to introduce new data type. Array an ordered set with the same data type.10 90 5 6 9 7 3 1int a82 3 6 54 0 8 1int a24int no , char name20 , float s1, s2, s3, s4one student: strutrueWhat is StructureStructure1 Structure is a advanced data type in C.2 Structure is a method for grouping a several related data type together. 3 Variables with different types can be grouped in a structureThe simple variables : int a , b;a=20, b=85; - invidualArray ： float grade20; same type relatedgrade0 grade1 grade2 grade3 What is Structurenum name grade1 grade210 Li 90.5 A11 Liu 80 B12 Wen 88 B. int char float char How can we define related data that have different type ?struct int num;char name10;float grade1;char grade2; ; What is StructureAll variables with the same types can be grouped in a array.wang 98 88 98 87li 87 66 83 67zhan 78 87 75 61liu 90 76 81 72zhao 87 81 74 71All variables with different types can be grouped in a structureContent name age sex addwang 18 m 3-110li 20 f 7-121liu 17 f 7-212zhao 18 m 3-222structure members ( type ,name)Structure variables Definition132A structure is a collection of related variables, any number of type of variables may be included within it.Defining structure,then declaring struct variables.Defining structure and struct variables.structure s name can be omitted keyword struct Structure members Sturcture variables Structure variable valuesstruct name type1 member 1;type2 member 2; typen member n; ;1 Defining structure,then declaring struct variables.Definitionstruct student int num;char name10;float grade1;char grade2; ; Structure is only as structure template, not occupying memory, because no any variable yet.A) Defining structure num name grade1 grade2struct datachar name20;int age;char address30;long telephone; struct struct_name struct_variable_name;struct data wang; struct data li,zhang; DefinitionB) Declaring structure variable name age address telephonename20age20 bytes2 bytes30 bytes4 bytesaddresstelephonename20ageaddress30telephonestruct data char name20;int age;char address30;long telephone;struct data wang;After declaration, computer will assign memory units to them. Definitionmain ( ) char str20;struct date int year, month, day; today; struct address char name30, street40, city20, state2;unsigned long int zip; wang; printf(“char: %dt“, sizeof(char); printf(“int: %dt”, sizeof(int); printf(“long: %dt“, sizeof(long); printf(“float: %dn“, sizeof(float); printf(“double: %dt“, sizeof(double); printf(“str: % dt“, sizeof(str); printf(“date: % dt“, sizeof(struct date); printf(“wang: % dn”, sizeof (wang ) ); Definition2 . Defining structure and struct variables.struct name type1 member 1;type2 member 2; typen membern; variable 1, variable2;struct student int num;char name20;char sex;int age;float score;char addr30;stu1,stu2; num name sex age score addstu1stu2Definition3 .structure s name can be omittedstruct type1 member 1;type2 member 2; typen membern; variable 1, variable2;struct int num;char name20;char sex;int age;float score;char addr30; stu1,stu2; Definitionnum name sex age score addr201 wang M 20 95 Zhongguancun road202 li F 19 80 Guangda GardenInitializationstruct student int num;char name20;char sex;int age;char addr30; struct student stu1= 112,“Wang Lin”,M,19, “200 Beijing Road”; When defining structure , assign values to each struct_variable (each member) one by one . Should be agreed with the type of corresponding members.struct student int num;char name20;char sex;int age;char addr30; stu1= 112,“Wang Lin” , M, 19, “200 Beijing Road” ; struct int num;char name20;char sex;int age;char addr30; stu1= 112,“Wang Lin”,M,19, “200 Beijing Road” ; InitializationHow to use these values? Access structure membersstud1 . grade1=95;stud1 . grade2=A;where “ . ” is calledmember operator.struct_ var_name . member_name struct int num;char name10;float grade1;char grade2 ; stud1,stud2,stud3; scanf ( “ %s , %f , %c, ”, printf ( “ %s , %f , %c , ”, , stude2 grade1, stude2 grade2);/* assignment */main( ) struct char initial; /* last name initial */ int age; /* childs age */int grade; /* childs grade in school */ boy , girl;boy.initial = R;boy.age = 17;boy.grade = 75;girl.age = boy.age - 1; /* she is one year younger */girl.grade = 82;girl.initial = H;printf(“%c is %d years old and got a grade of %dn“,girl.initial, girl.age, girl.grade);printf(“%c is %d years old and got a grade of %dn“,boy.initial, boy.age, boy.grade);Access structure membersOne structure may be nested within work address Home addresspost addr tel post addr telstruct address int postchar addr100;char tel20; ;struct personal char name20;struct address workaddr ;struct address homeaddr ; ;struct_var_name. out_mem . inner_memmain ( ) struct date /* structure type date */int year, month, day; ;struct date today; /* stru-var today */printf (“Enter today date:“);scanf(“%d %d %d”, printf(“%d.%d.%dn ”, today.year,today.month,today.day ); datechar sex;struct int year;int month;int day; birth; ;struct student s;A)year=1982month=11day=11B)birth.year=1982,birth.month=11birth.day=11C)s.year=1982s.month=11s.day=11D) s.birth.year=1982s.birth.month=11s.birth.day=11If the birthday is “11 / 11 /82”， which is the correct assignment statement?Access structure members1 DefinitionForm1 struct student int num;char name20;char sex;int age;struct student stu30;Form2 struct student int num;char name20;char sex;int age;stu30;Form3 struct int num;char name20;char sex;int age;stu30;Array group several related variables with the same type, store in sequence30 studentsIn one classThe type is structureStructure and arrayThe relationship between structure and array Array is a member of a structure An array which members are all structure variablenum Name Score0 Score1101 wang 90 98110 zhan 87 75struct int num ;char name20;float score2; stu1,stu2;num Name Score0 Score1101 wang 90 98110 zhan 87 75struct int num ;char name20;float score2; stu2;Structure and arrayInitualizationstruct stud int xh;struct stud xscj3 , , ; OR： struct stud int xh; xscj3 , , ; Data in one arrayStructure and arrayAccess members of structure arraymain() struct xscj xs4=“01“,70,80,“02“,78,67,“03“,56,78,“04“,90,80;int i;for (i=0;imember-of-structure refers to the particular member.To access the member of structure by pointer(*pointer name ).member namepointer name -member name1 Points to the structure variablestruct xscjchar *xh;float cj2;float av;xs=“02“,78,67;main() struct xscj *p=p-av=(p-cj0+p-cj1)/2;printf(“%s,%5.1f,%5.1f,%5.1fn“,p-xh,p-cj0,p-cj1,p-av);Structure and pointeroutput：02, 78.0, 67.0, 72.5Declaration of structureDeclaration and initualization of structure variableDeclaration and initualization of structure pointerAccess the structure member by pointerPoints to the structure array main() struct xscj xs4=“01“,70,80,“02“,78,67,“03“,56,78,“04“,90,80 ;struct xscj *p;for (p=xs;pav=(p-cj0+p-cj1)/2.0;printf(“%s,%5.1f,%5.1f,%5.1fn“,p- xh,p-cj0,p-cj1,p-av);struct xscjchar *xh;float c