Declarations and Initializations Questions

• Identify the construct that is not a user-defined data type in C/C++ among the following: (1) struct book { char name[10]; float price; int pages; }; (2) long int l = 2.35; (3) enum day { Sun, Mon, Tue, Wed };
• C/C++ declarations: Is there any difference between the following function declarations—(1) extern int fun(); and (2) int fun();—when no function body is provided?
• C/C++ fundamentals: At what stage do we 'mention' (provide) the prototype of a function—defining, declaring, prototyping, or calling?
• C linkage example: In the program shown, where is variable 'a' declared and where is it defined? (extern int a; ... int a = 20;)
• C math library: Which statement correctly obtains the remainder of dividing 3.14 by 2.1 in floating-point arithmetic?
• C/C++ language basics: Is the statement 'extern int i;' a declaration or a definition?
• C math rounding: Which function call rounds 1.66 upward to 2.0 according to standard C/C++ library rules?
• C language linkage: Which types of linkages are recognized for identifiers in C—considering scope and visibility across translation units?
• C/C++ declarations: Which among the following lines are declarations (not definitions) — 1) extern int x; 2) float square(float x) { /* ... / } 3) double pow(double, double);
• C/C++ literals: By default, a real (floating) numeric literal such as 3.5 is treated as which type?
• C identifier rules: Which special symbol is allowed within a variable name according to standard C/C++ naming conventions?
• In C (16-bit Turbo C under DOS), what will this program output, considering 'extern' without a definition and assignment before any definition? #include int main() { extern int i; // declaration only, no definition here i = 20; // assignment requires a definition to exist at link time printf("%d ", sizeof(i)); // sizeof uses the type, not the object return 0; }
• In C, what output is produced by the following enumeration and assignments (default enum starting at 0)? #include int main() { enum status { pass, fail, atkt }; enum status stud1, stud2, stud3; stud1 = pass; // 0 stud2 = atkt; // 2 stud3 = fail; // 1 printf("%d, %d, %d ", stud1, stud2, stud3); return 0; }
• C extern and definition order: what does this program print when a global is defined after main? #include int main() { extern int a; // declaration printf("%d ", a); return 0; } int a = 20; // definition after main is valid
• In C, when a local variable shadows a global of the same name, which value prints? #include int X = 40; // global int main() { int X = 20; // local shadowing global printf("%d ", X); return 0; }
• C prototype mismatch and argument promotions: what happens here (Turbo C style)? #include int main() { extern int fun(float); // prototype says: takes float, returns int int a; a = fun(3.14); // call with float literal printf("%d ", a); return 0; } int fun(int aa) // actual definition: takes int, returns int { return (int)++aa; }
• For-loop with scanf in the test expression: how many times does this loop execute (conceptually)? #include int main() { int i = 5; for ( ; scanf("%s", &i); printf("%d ", i) ); return 0; }
• Array partial initialization in C: given only the first two elements, what prints? #include int main() { int a[5] = {2, 3}; // remaining elements implicitly zero printf("%d, %d, %d ", a[2], a[3], a[4]); return 0; }
• Turbo C (16-bit, DOS): sizes of near, far, and huge pointers when printed via sizeof on pointer variables #include int main() { char *s1; // near pointer (default model) char far *s2; // far pointer char huge *s3; // huge pointer (normalized, same size as far) printf("%d, %d, %d ", sizeof(s1), sizeof(s2), sizeof(s3)); return 0; }
• Chained relational operators in C: how is this expression evaluated? #include int main() { int x = 10, y = 20, z = 5, i; i = x < y < z; // left-to-right evaluation with boolean 0/1 printf("%d ", i); return 0; }