What is the output of this C code?
void main()
{
int x;
}
here x is a
Answer: A
Correct answer: automatic variable
x is declared inside a function with no storage class, so it is automatic by default - on the stack, uninitialised, and gone when main returns.
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If a function contains two return statements successively, the compiler will generate warnings. Yes/No ?
Answer: A
Correct answer: Yes
Two return statements one after the other make the second unreachable: the first ends the function. Compilers warn about unreachable code because it almost always means the author intended something else.
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Automatic variables are stored in:
Answer: A
Correct answer: stack
Automatic variables are allocated on the stack: space is reserved when the block is entered and released when it is left, which is what makes their lifetime match the block and what makes recursion possible - each call gets its own frame.
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What are automatic variables initialised to?
Answer: A
Correct answer: Junk value
An automatic variable is not initialised: it holds whatever bytes were left on the stack by earlier calls. Reading one before assigning to it is undefined behaviour, and the value is unpredictable - which is why compilers warn about it.
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In a function two return statements should never occur.
Answer: B
Correct answer: No
Several return statements in one function are perfectly ordinary - one per branch is the common pattern, and it often reads better than forcing a single exit. What should not happen is two consecutive returns, since the second can never be reached.
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What will be the output?
double var = 8;
int main()
{
int var = 5;
printf("%d", var);
}
Answer: A
Correct answer: 5
The local int var = 5; shadows the file-scope double var = 8; throughout main, so %d is matched with an int and prints 5. Shadowing is legal - the two are different objects in different scopes.
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Automatic variables:
Answer: D
Correct answer: Both (a) & (b)
Both statements describe the same property from two sides: an automatic variable exists only within its block, and it ceases to exist when the block is left. Its storage on the stack is reclaimed at once, which is why returning a pointer to one is a bug.
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Where are automatic variables allocated memory?
Answer: D
Correct answer: stack
Automatic variables are allocated on the stack: space is reserved when the block is entered and released when it is left, which is what makes their lifetime match the block and what makes recursion possible - each call gets its own frame.
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What is the output of this C code?
static int x = 5;
void main()
{
x = 9;
{
int x = 4;
}
printf("%d", x);
}
Answer: A
Correct answer: 9
x = 9; assigns to the file-scope static variable, and the inner block’s int x = 4; declares a different variable that vanishes at the closing brace. So the printf, back outside, shows 9.
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Which of the following function declarations is illegal?
Answer: D
Correct answer: All of the mentioned
All three are illegal for the same reason: a C identifier cannot begin with a digit. 1bhk and 2bhk are not valid names, whatever their parameter lists.
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