61. What is the output of: printf("%d", 1 < 2 ? 3 : 4, 5);
- a) 1
- b) 3
- c) 5
- d) Compilation warning
Answer: B - The ternary operator returns 3 (since 1<2 is true), and the 5 is an extra unused argument.
62. Which of these is NOT a valid C11 atomic type qualifier?
- a) _Atomic
- b) atomic_int
- c) atomic_bool
- d) atomic_float
Answer: D - atomic_float is not a standard atomic type (C11 has atomic_int, atomic_bool, etc.).
63. What is the purpose of the 'complex' keyword in C?
- a) Complex control flow
- b) Complex numbers support
- c) Complex data structures
- d) Complex macros
Answer: B - complex (and _Complex) are used for complex number support (requires complex.h).
64. What is the output of: printf("%d", 1 | 2 & 3);
- a) 1
- b) 2
- c) 3
- d) 4
Answer: C - & has higher precedence than |, so 2&3=2, then 1|2=3.
65. Which function is used to set the FPU rounding direction?
- a) fesetround()
- b) fsetround()
- c) setfround()
- d) roundset()
Answer: A - fesetround() from fenv.h sets floating-point rounding direction.
66. What is the value of: (struct {int x;}*)0
- a) NULL pointer
- b) Pointer to address 0
- c) Compilation error
- d) Runtime error
Answer: B - This is a null pointer of type "pointer to struct", not necessarily NULL macro.
67. Which of these is NOT a valid C99 math library function?
- a) log2()
- b) exp2()
- c) pow2()
- d) hypot()
Answer: C - pow2() doesn't exist (use pow(2,x) or exp2(x) instead).
68. What is the output of: printf("%d", sizeof(1==1));
- a) 1
- b) 2
- c) 4
- d) Compiler dependent
Answer: C - In C, boolean expressions result in int (typically 4 bytes), not bool type.
69. What is the purpose of the 'noreturn' attribute?
- a) Prevent function returns
- b) Optimize tail calls
- c) Mark non-returning functions
- d) Disable recursion
Answer: C - _Noreturn (C11) or __attribute__((noreturn)) indicates functions don't return.
70. What is the output of: printf("%d", 0 || !1 && 1);
- a) 0
- b) 1
- c) 2
- d) Compilation error
Answer: A - && has higher precedence than ||: !1=0, 0&&1=0, then 0||0=0.
71. Which function is used to query FPU exception flags?
- a) fegetexceptflag()
- b) fetestexcept()
- c) fexcepttest()
- d) fpuexcept()
Answer: B - fetestexcept() from fenv.h tests floating-point exceptions.
72. What is the value of: (int){3.14}
- a) 3
- b) 3.14
- c) Compilation error
- d) Undefined behavior
Answer: C - Cannot use compound literal with cast (invalid syntax).
73. Which of these is NOT a valid C11 threading feature?
- a) thrd_create()
- b) mtx_lock()
- c) cnd_wait()
- d) tls_get()
Answer: D - C11 uses thread_local for TLS, not tls_get() function.
74. What is the output of: printf("%d", 1 * 2 + 3 / 4);
- a) 0
- b) 1
- c) 2
- d) 3
Answer: C - * and / have same precedence: 3/4=0 (integer division), then 1*2+0=2.
75. What is the purpose of the 'quick_exit()' function?
- a) Fast program termination
- b) Thread termination
- c) Signal handling
- d) Process forking
Answer: A - quick_exit() (C11) terminates program without calling full cleanup.
76. What is the output of: printf("%d", 1 << 32); (32-bit int)
- a) 0
- b) 1
- c) Undefined behavior
- d) Compilation error
Answer: C - Shifting by >= width of type is undefined behavior.
77. Which function is used to copy memory between overlapping regions?
- a) memcpy()
- b) memmove()
- c) mempcpy()
- d) bcopy()
Answer: B - memmove() safely handles overlapping memory regions.
78. What is the value of: (int){1} + 2
- a) 1
- b) 2
- c) 3
- d) Compilation error
Answer: D - Compound literals can't be used in expressions this way.
79. Which of these is NOT a valid C11 alignment feature?
- a) alignas
- b) alignof
- c) _Alignas
- d) memalign
Answer: D - memalign() is a POSIX function, not C11 standard.
80. What is the output of: printf("%d", 1 ?: 2);
- a) 0
- b) 1
- c) 2
- d) Compilation error
Answer: B - The GNU extension ?: (omitted middle operand) returns the condition if true.