Free Test Difference between str... – C Language

Q1: What is the key difference between a structure and a union?

A. Structure allocates memory for all members separately; union allocates shared memory B. Both allocate shared memory C. Structure allocates memory only for first member; union for all members D. Both allocate memory for only one member

Q2: In terms of memory size, how does a struct compare to a union?

A. Struct size is sum of all members; union size is size of largest member B. Struct size is size of largest member; union size is sum of members C. Both have same size D. Struct size is always smaller

Q3: Can both structs and unions have nested members?

A. Yes, both can be nested B. Only structs C. Only unions D. Neither

Q4: How are members accessed in struct and union?

A. Both use dot operator B. Struct uses arrow operator; union uses dot operator C. Struct uses dot operator; union uses arrow operator D. Both use arrow operator

Q5: Which allows all members to store different values simultaneously?

A. Structure B. Union C. Neither D. Both

Q6: Which data type is typically used for memory-efficient storage?

A. Union B. Structure C. Both equal D. None

Q7: Which allows type punning and accessing the same memory as different types?

A. Union B. Structure C. Both D. Neither

Q8: When you assign values to multiple members, which retains only last assigned value?

A. Union B. Structure C. Both D. Neither

Q9: How does alignment affect structs and unions?

A. Both follow alignment rules, but struct size sums aligned members B. Union ignores alignment C. Structs are not aligned D. Unions always align to 1 byte

Q10: Can both structs and unions have bit-fields?

A. Yes B. Only structs C. Only unions D. No

Q11: Which can be initialized at declaration with multiple members?

A. Struct B. Union C. Both D. Neither

Q12: Are pointers to structs and unions used differently?

A. No, usage is similar B. Yes, unions need special syntax C. Struct pointers are faster D. Union pointers are safer

Q13: Which allows storing multiple members' values at the same time?

A. Struct B. Union C. Both D. None

Q14: How do you define a struct with alias "Person"?

A. typedef struct { int age; } Person; B. typedef union { int age; } Person; C. struct Person { int age; }; D. union Person { int age; };

Q15: What happens to union members when you assign to one member?

A. Other members' values become undefined B. All members keep their values C. Compilation error D. Runtime error

Q16: Which is preferred when data members are mutually exclusive?

A. Union B. Struct C. Both D. None

Q17: How is the memory layout different for struct vs union?

A. Struct: sequential; Union: overlapping B. Struct: overlapping; Union: sequential C. Both sequential D. Both overlapping

Q18: Is it possible to use sizeof operator on struct and union?

A. Yes, returns size of struct or largest union member B. No, only for struct C. No, only for union D. No, for neither

Q19: Which keyword is used for both struct and union definitions?

A. struct and union respectively B. class C. typedef D. define

Q20: Can structs and unions be used in function parameters?

A. Yes, both can be passed by value or pointer B. Only structs C. Only unions D. No

Quiz for Difference between structures and unions