Example : Define a structure of student having fields Roll No, Name, Address and fees paid ( Make appropriate assumption about datatypes) Method -1

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1 Structure Structure is a user defined data type, it is used to combine different types of available data type(s) to form a new data type, to suite a real life problem. The syntax of a structure is as follows Syntax struct <identifietr> Datatype <identifier>; Datatype <identifier>; Datatype <identifier>; Example : Define a structure of student having fields Roll No, Name, Address and fees paid ( Make appropriate assumption about datatypes) Solution struct student How to define structure type variable(s) roll; name[30]; address[60]; Method -1 struct student s ; roll; name[30]; address[60]; Declaration of structure and variable simultaneously Method -1I struct student Student s; ; roll; name[30]; address[60]; Declaration of variable after declaration of student type structure Note : The above declaration ( any ) of variable create a new memory block named as S. This is further divided o four parts namely, roll, name, address and fees. These block now contains some garbage values. S Roll Name Address Fees These block can be accessed using DOT OPERATOR (.) i,e if you want to access roll sub-block of S block then you have to write Page 1 of 8

2 s.roll Initialization method of structure variable Method-1 struct student address[60]; s =1, ramji, b-100 surya nagar, Method-1I struct student address[60]; student s =1, ramji, b-100 surya nagar, Method-1II struct student address[60]; s.roll =1; strcpy(s.name, Ramji ); strcpy(s.address, b-100 surya nagar ); s.fees =125.75; Method-1V struct student address[60]; cin>>s.roll >>s.name>>s.address>>s. Method-V struct student address[60]; s =1, ramji, b-100 surya nagar, student s1; Task : Initialize variable s1 using variable s Method 5.1 S1=S; Methos 5.2 s1.roll = s.roll; strcpy(s1.name,s.name); Page 2 of 8

3 strcpy(s1.address, s.address); s1.fees = s. Nested Structure : if a structure is used inside another structure then it is called nested structure or embedded structure. Task : Define a structure of student having following structure diagram Roll No Name Address fees First Second The above mentioned problem can be solved using two method Method I struct stud_name Char first[15]; struct student Char stud_name second[15]; rollno; name; address[80]; Note : Method-II struct student rollno; struct stud_name name; address[80]; first[15]; second[15]; Example :Define a structure of student having fields roll, name, marks obtained in three subject physics, chemistry, mathematics, computer and English, total marks and percentage. Write a program in C++ to read a record of student. Calculate total marks and percentage. Display the same record on the screen. Solution Program Page 3 of 8

$struct student phy; chem; math; comp; eng; total; per; //input phase cout<<"\n Enter roll number :"; cin>>s.roll; cout<<"\n Enter name :"; cin>>s.$

4 struct student phy; chem; math; comp; eng; total; per; //input phase cout<<"\n Enter roll number :"; cin>>s.roll; cout<<"\n Enter name :"; cin>>s.name; cout<<"\n Enter marks obtained in physics :"; cin>>s.phy; cout<<"\n Enter marks obtained in chemistry :"; cin>>s.chem; cout<<"\n Enter marks obtained in maths :"; cin>>s.math; cout<<"\n Enter marks obtained in Computer :"; cin>>s.comp; cout<<"\n Enter marks obtained in English :"; cin>>s.eng; // processing phase s.total = s.phy+s.chem+s.math+s.comp+s.eng; s.per = s.total *100/500.0; //output Phase cout<<"\n Roll No. :"<<s.roll; cout<<"\n Physics :"<<s.phy; cout<<"\n Chemistry :"<<s.chem; cout<<"\n Mathematics :"<<s.math; cout<<"\n Total marks :"<<s.total; cout<<"\n Percentage :"<<s.per; Array of structure : The above mentioned program is designed to hold the record of a single student, if you want to store and process more records than a possible solution is array of structure How to define and use array of structure Q1. Define a structure of student having fields roll, name, marks obtained in three subject physics, chemistry, mathematics, computer and English, total marks and percentage. Write a program in C++ to read the record of 10 student. Calculate total marks and percentage. Display the same records on the screen. Program Page 4 of 8

$struct student phy; chem; math; comp; eng; total; per; student s[10]; i; //input phase for(i=0;i<3;i++) cout<<"\n Enter roll number :"; cin>>s[i].roll; cout<<"\n Enter name :"; cin>>s[i].$

5 struct student phy; chem; math; comp; eng; total; per; student s[10]; i; //input phase for(i=0;i<3;i++) cout<<"\n Enter roll number :"; cin>>s[i].roll; cout<<"\n Enter name :"; cin>>s[i].name; cout<<"\n Enter marks obtained in physics :"; cin>>s[i].phy; cout<<"\n Enter marks obtained in chemistry :"; cin>>s[i].chem; cout<<"\n Enter marks obtained in mathematics :"; cin>>s[i].math; cout<<"\n Enter marks obtained in Computer :"; cin>>s[i].comp; cout<<"\n Enter marks obtained in English :"; cin>>s[i].eng; // processing phase for(i=0;i<3;i++) s[i].total = s[i].phy+s[i].chem+s[i].math+s[i].comp+s[i].en g; s[i].per = s[i].total *100/500.0; //output Phase for(i=0;i<3;i++) cout<<"\n Roll No. :"<<s[i].roll; cout<<"\n Name :"<<s[i].name; cout<<"\n Physics :"<<s[i].phy; cout<<"\n Chemistry :"<<s[i].chem; Page 5 of 8

$cout<<"\n Mathematics cout<<"\n Total marks cout<<"\n Percentage :"<<s[i].math; :"<<s[i].total; :"<<s[i].$

6 cout<<"\n Mathematics cout<<"\n Total marks cout<<"\n Percentage :"<<s[i].math; :"<<s[i].total; :"<<s[i].per; Passing Structure as a function Parameter : Structure can be passed as a function parameter as shown in the following example. Task : Define a structure of student having fields name and roll no. Write a program to read name and roll number and pr the value of this structure using a function Pr( ). Possible Solution : I ( improper) struct student void pr( x, y[]) cout<<"\n Roll No :"<<x; cout<<"\n Name :"<<y; student s=10,"rakesh Kumar" pr(s.roll,s.name); II ( Proper Solution) struct student void pr( student s) student s=10,"rakesh Kumar" pr(s); Structure as a function return type value : Program struct student Page 6 of 8

$student read_data(void) cout<<"\n Enter roll no :"; cin>>s.roll; cout<<"\n Enter name :"; cin>>s.$

7 student read_data(void) cout<<"\n Enter roll no :"; cin>>s.roll; cout<<"\n Enter name :"; cin>>s.name; return (s); s= read_data(); Passing structure as a call value method in a function program #include<string.h> struct student void change( student s) // parameter as value s.roll=100; strcpy(s.name,"ramji"); student s=10,"rakesh Kumar" cout<<"\n Before function call\n"; change(s); cout<<"\n after function call by value\n"; No Change in the output as the value is passed in the function as a value. Page 7 of 8

8 cout<<"\n Name :"<<s.name; Passing structure as a call by reference method in a function Program #include<string.h> struct student void change( student & s) // parameter as reference s.roll=100; strcpy(s.name,"ramji"); student s=10,"rakesh Kumar" cout<<"\n Before function call\n"; change(s); cout<<"\n after function call by value\n"; Changes made inside function is visible in the main program as value had been passed as reference Page 8 of 8

Chapter-14 STRUCTURES

Chapter-14 STRUCTURES Introduction: We have seen variables of simple data types, such as float, char, and int. Variables of such types represent one item of information: a height, an amount, a count, and