Functions Questions and Answers

Q: Is an assignment statement that gives a value to a local static variable executed only once?

Correct answer: falseThe initialisation of a static variable happens once, before the program starts. But an ordinary assignment to it inside the function is an executable statement like any other, and runs every time the function is called - which would defeat the whole point of making the variable static.

Q: Which of the following is the correct form of a function declaration?

Correct answer: return-type function-name(argument type);A declaration (prototype) states the return type, the name and the parameter types, and ends with a semicolon - no body. Adding a body makes it a definition, which is a different thing.

Q: What is the output of this C code? void foo(); int main() { void foo(); foo(); return 0; } void foo() { printf("2 "); }

Correct answer: 2The function is declared at file scope and again inside main. Repeating a declaration is harmless as long as the two agree, which they do, so the program compiles and prints 2.

Q: Which of the following storage classes supports the char data type?

Correct answer: All of the mentionedchar works with every storage class: auto char, static char and register char are all valid. Storage class and type are independent choices - the first says where and how long the object lives, the second what it holds.

Q: What is the output of this C code? int main() { void foo(), f(); f(); } void foo() { printf("2 "); } void f() { printf("1 "); foo(); }

Correct answer: 1 2Declaring void foo(), f(); inside main is legal - it declares them, without defining them, and the declaration is simply local in scope. f() is then called; it prints 1 and calls foo, which prints 2. Output: 1 2.

Q: What is the format identifier for “static a = 20.5;”?

Correct answer: %dWith no type given, static a = 20.5; falls back on the old implicit int, so the value is truncated to 20 and the correct specifier is %d. The declaration is legal only under the pre-C99 rules; a modern compiler will warn or reject it.

Q: Functions have the static qualifier by default.

Correct answer: falseFunctions have external linkage by default, not static - which is why a function defined in one file can be called from another. Writing static before a function is what confines it to its own file.

Q: The value computed in a function is given back to the caller using the ________ keyword.

Correct answer: returnreturn both ends the function and passes the value back. static, new and volatile have nothing to do with it - and new is not even a C keyword.

Q: What is the problem in the following declarations? int func(int); double func(int); int func(float);

Correct answer: All of the mentionedC has no function overloading: one name may denote only one function in a translation unit. So none of the three variations is allowed - not a different signature, not a different return type, not a different number of parameters. (C++ permits overloading on the parameters, though still not on the return type alone.)

Q: Array sizes are optional during array declaration by using ______ keyword.

Correct answer: externAn extern declaration says the array is defined elsewhere, so its size may be omitted: extern int a[];. The definition in the other file supplies the size. Note the consequence - sizeof cannot be applied to it in this file, since the compiler does not know how big it is.

21.

Is an assignment statement that gives a value to a local static variable executed only once?

A.true
B.false
C.Depends on the code
D.None of the mentioned

Answer: B

Correct answer: false

The initialisation of a static variable happens once, before the program starts. But an ordinary assignment to it inside the function is an executable statement like any other, and runs every time the function is called - which would defeat the whole point of making the variable static.

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22.

Which of the following is the correct form of a function declaration?

A.return-type function-name(argument type);
B.return-type function-name(argument type) {}
C.return-type (argument type)function-name
D.Both (a) and (b)

Answer: A

Correct answer: return-type function-name(argument type);

A declaration (prototype) states the return type, the name and the parameter types, and ends with a semicolon - no body. Adding a body makes it a definition, which is a different thing.

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23.

What is the output of this C code?

void foo();
int main()
{
void foo();
foo();
return 0;
}
void foo()
{
printf("2 ");
}

A.Compile time error
B.2
C.Depends on the compiler
D.Depends on the standard

Answer: B

Correct answer: 2

The function is declared at file scope and again inside main. Repeating a declaration is harmless as long as the two agree, which they do, so the program compiles and prints 2.

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24.

Which of the following storage classes supports the char data type?

A.register
B.static
C.auto
D.All of the mentioned

Answer: D

Correct answer: All of the mentioned

char works with every storage class: auto char, static char and register char are all valid. Storage class and type are independent choices - the first says where and how long the object lives, the second what it holds.

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25.

What is the output of this C code?

int main()
{
void foo(), f();
f();
}
void foo()
{
printf("2 ");
}
void f()
{
printf("1 ");
foo();
}

A.Compile time error as foo is local to main
B.1 2
C.2 1
D.Compile time error due to declaration of functions inside main

Answer: B

Correct answer: 1 2

Declaring void foo(), f(); inside main is legal - it declares them, without defining them, and the declaration is simply local in scope. f() is then called; it prints 1 and calls foo, which prints 2. Output: 1 2.

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26.

What is the format identifier for “static a = 20.5;”?

A.%s
B.%d
C.%f
D.Illegal declaration due to absence of data type

Answer: B

Correct answer: %d

With no type given, static a = 20.5; falls back on the old implicit int, so the value is truncated to 20 and the correct specifier is %d. The declaration is legal only under the pre-C99 rules; a modern compiler will warn or reject it.

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27.

Functions have the static qualifier by default.

A.true
B.false
C.Depends on the compiler
D.Depends on the standard

Answer: B

Correct answer: false

Functions have external linkage by default, not static - which is why a function defined in one file can be called from another. Writing static before a function is what confines it to its own file.

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28.

The value computed in a function is given back to the caller using the ________ keyword.

A.return
B.static
C.new
D.volatile

Answer: A

Correct answer: return

return both ends the function and passes the value back. static, new and volatile have nothing to do with it - and new is not even a C keyword.

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29.

What is the problem in the following declarations?
     int func(int);
     double func(int);
     int func(float);

A.A function with same name cannot have different signatures
B.A function with same name cannot have different return types
C.A function with same name cannot have different number of parameters
D.All of the mentioned

Answer: D

Correct answer: All of the mentioned

C has no function overloading: one name may denote only one function in a translation unit. So none of the three variations is allowed - not a different signature, not a different return type, not a different number of parameters. (C++ permits overloading on the parameters, though still not on the return type alone.)

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30.

Array sizes are optional during array declaration by using ______ keyword.

A.auto
B.static
C.extern
D.register

Answer: C

Correct answer: extern

An extern declaration says the array is defined elsewhere, so its size may be omitted: extern int a[];. The definition in the other file supplies the size. Note the consequence - sizeof cannot be applied to it in this file, since the compiler does not know how big it is.

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