Exploring C Structures, Unions, and Files

What is the syntax to define a structure in C?

• StructName struct { memberName dataType; };

• struct StructName: dataType memberName;

• struct StructName { dataType memberName; };

• struct { memberName: dataType } StructName;

How do you access a member of a structure in C?

• Access members using the asterisk operator (*) only.

• Use the semicolon operator (;) to access members.

• Use the dot operator (.) or the arrow operator (->) depending on whether you have a structure variable or a pointer.

• Members can be accessed by their index number like arrays.

What is the primary difference between a structure and a union in C?

• A structure can hold only one value at a time, while a union can hold multiple values simultaneously.

• Structures and unions are identical in functionality and usage.

• A structure can only contain primitive data types, while a union can contain complex data types.

• A structure can hold multiple values simultaneously, while a union can hold only one value at a time.

How do you define a union in C?

• union union_name { data_type1 member1; data_type2 member2; ... };

• enum enum_name { value1, value2, ... };

• class class_name { data_type1 member1; data_type2 member2; ... };

• struct struct_name { data_type1 member1; data_type2 member2; ... };

What happens to the memory allocation of a union when a new member is assigned?

• The memory allocation remains the same; it is shared among all members.

• The memory allocation is reset to zero when a new member is assigned.

• Memory is allocated separately for each member of the union.

• The memory allocation increases for each new member assigned.

Can a structure contain a union as a member?

• Yes, a structure can contain a union as a member.

• No, a union cannot be a member of a structure.

• Only classes can contain unions as members.

• Structures and unions are mutually exclusive.

What is the purpose of the 'sizeof' operator in relation to structures?

• The 'sizeof' operator calculates the number of elements in a structure.

• The 'sizeof' operator is used to define a structure's members.

• The 'sizeof' operator determines the size of a structure in bytes.

• The 'sizeof' operator converts a structure to a string representation.

How do you read a structure from a file in C?

• Read the file using 'read' system call.

• Use 'fread' or 'fscanf' after opening the file with 'fopen'.

• Use 'printf' to display the structure directly.

• Use 'fwrite' to write the structure to the file.

What function is used to open a file in C?

• readfile

• fileopen

• fopen

• openfile

What is the difference between 'fopen' and 'freopen' in C?

• 'fopen' closes a file, 'freopen' opens a file.

• 'fopen' can only read files, 'freopen' can only write files.

• 'fopen' is used for binary files, 'freopen' is used for text files.

• 'fopen' opens a new file, 'freopen' reopens an existing file stream.