Declarations and Initializations Questions and Answers

Answer: A

Only P1 will compile without any error.

P1 declares a global int a=5; and a local int a=7; inside main. These are in different scopes, so the local declaration simply hides the global one inside main. That is legal C.

P2 declares int a twice in the same block scope. C does not allow two definitions of the same identifier in one block, so this is a redeclaration error.

P3 declares a as an int and then as a float in the same block: a conflicting-types error. So only P1 compiles, which rules out the other three options.

Answer: A

Correct answer: Compile time error

The same identifier is declared twice in one scope with different types, which the language forbids: k cannot be both an int and a float. The error is diagnosed at compile time, so no output is produced at all.

Answer: A

Correct answer: Yes

The inner braces open a new block, and a declaration in an inner block may reuse a name from an outer one - the inner k simply shadows the outer for the extent of that block. It is legal, though the shadowing is a common source of confusion and most compilers will warn about it.

Answer: D

Correct answer: char[] str = “...”;

C writes the brackets after the identifier, not after the type: char str[]. The form with the brackets before the name belongs to Java. The other three are all valid ways of holding a string, though the third truncates if the literal exceeds the declared size.

Answer: B

Correct answer: External, Internal and None

Three linkages exist. External linkage makes a name visible across translation units, internal linkage confines it to one file - which is what static at file scope gives - and no linkage belongs to block-scope names, each declaration of which denotes a distinct object.

Answer: A

Correct answer: ceil(1.66)

ceil returns the smallest integer not less than its argument, so 1.66 becomes 2.0. floor would give 1.0, and neither roundup nor roundto exists in the standard library - the standard rounding function is round.

Answer: B

Correct answer: No

A name with external linkage is visible to every function that declares it, and nothing distinguishes one function from another. What can be restricted is the file: declaring the variable static at file scope confines it to that translation unit. The granularity is the file, not the function.

Answer: A

Correct answer: %f

var is a pointer to char, so %s prints the string, and %d or %c could at least be applied to the pointer value or to a dereferenced character. %f expects a double and could never be given anything derived from this variable, which is what makes it the answer.

Answer: C

Correct answer: rem = fmod(3.14, 2.1);

The % operator is defined only for integer operands and will not compile with doubles. fmod from math.h is the floating point equivalent and returns 1.04 here. modf is unrelated - it splits a value into its integer and fractional parts.

Answer: A

Correct answer: Yes

A prototype may appear in every file that calls the function, and usually does by way of a header, but the body is written once. The rule is the same as for objects: declarations may be repeated, and the definition may not.