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Student newStudent = { "C0681008","Cao Anh Huy", 8.50,{1, 2, 1985} };

Notice how we include the initialization values in curly brackets, just like when we initialize an array. Furthermore, we include the values for any nested structure type (in this case the dateOfBirth member is a nested structure), in a further set of curly brackets.

Copying structure variables

One of the most convenient features of structures is that we can copy them in a single assignment operation. This is unlike an array, which must be copied item-by-item. The name of a structure variable when it appears on its own represents the entire structure. If a structure contains an array as a member, that array is copied if the entire structure is copied.

Student newStudent1, newStudent2; // Get the values for newStudent2... // Copy newStudent2's value to newStudent1newStudent1 = newStudent2;

Comparing values of structures

We cannot compare structures in a single operation. If we wish to compare the values of two structure variables, we need to compare each of their members.

Arrays of structures

Just as we can have an array of basic data types, we can also have an array of structures. Suppose that we created an array of Student structures as follows. We could then copy newStudent into each position in the array.

Student students[100];Student newStudent; int i;for (i=0; i<100; i++) {// Get the values for newStudent ...// Copy into the next position in the array students[i]= newStudent; }

Operations on structures

Passing structures to and from functions

Structures can be passed to functions just like any other data type. Functions can also return structures, just as they can return any basic type. Structures can be also be passed to functions by reference.

Just like passing variable of a basic data type, when we pass a structure as an argument to a function, a copy is made of the entire structure. Structures are passed by value. We can easily take the code that output a student and put it into a function as follows.

void outputStudent(Student stu) {printf("Student Details\n"); printf("Identification: %s\n", stu.studentID);printf("Name: %s\n", stu.name); printf("Mark: %.2f\n, stu.markCS);printf("Date of Birth: %i/%i/%i\n", stu.dateOfBirth.day,stu.dateOfBirth.month, stu.dateOfBirth.year); }

If we had an array of 100 students and wanted to output them this would be straightforward:

Student students[100];int i; ...for (i=0; i<100; i++) { outputStudent(students[i]); }

We could similarly place the code to input a student into a function, but now we have a problem. The function can return a structure of type Student as follows.

Student inputStudent() {Student tempStudent; printf("Enter Student identification: ");scanf("%s",&tempStudent.studentID); printf("Enter Student name: ");fflush(stdin);gets(tempStudent.name); printf("Enter final mark: ");scanf("%f",&tempStudent.markCS); printf("Enter birth date (dd/mm/yyyy):");scanf("%i/%i/%i",&tempStudent.dateOfBirth.day,&tempStudent.dateOfBirth.month,&tempStudent.dateOfBirth.year );return tempStudent; }

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Source:  OpenStax, Introduction to computer science. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10776/1.1
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