All Compiler Design questions

char *str1 = "Hello;    /* Statement S1 */
char *str2 = "Hello;";  /* Statement S2 */
int *str3 = "Hello";    /* Statement S3 */

One or more correct

• AS1 and S2 have syntactic errors
• BS2 has a lexical error and S3 has a syntactic error
• CS1 has a lexical error and S3 has a semantic error
• DS1 has a syntactic error and S3 has a semantic error

One or more correct

• ALL(1) parser uses backtracking
• BFor a grammar to be LL(1), it must be left-recursive
• CFor a grammar to be LL(1), it must be left-factored
• DThe LL(1) parsers are more powerful than the SLR parsers

Single correct

• AB4: $\{b + i\}$, B5: $\{c + m\}$
• BB4: $\{g * k\}$, B5: $\{c + m\}$
• CB4: $\{g * k,\ b + i\}$, B5: $\{\}$
• DB4: $\{g * k\}$, B5: $\{\}$

One or more correct

• AThe languages P and Q are the same
• BSDD2 is S-attributed and contains only synthesized attributes
• CSDD1 is L-attributed and contains only inherited attributes
• DThe specifications of SDD1 and SDD2 are such that the same entries get added to the symbol table

Single correct

• AA static variable declared inside a function
• BAn array of integers declared inside a function
• CA dynamically allocated array of integers created using malloc() function call
• DReturn address of a function

Numerical answer

Single correct

• A2
• B3
• C4
• D5

Single correct

• AB1: $\{a, b, c, e, f\}$, B2: $\{d, e\}$, B3: $\{b, c, e, f\}$, B4: $\emptyset$
• BB1: $\emptyset$, B2: $\{d, e\}$, B3: $\{a, c, f\}$, B4: $\emptyset$
• CB1: $\{a, b, c, e, f\}$, B2: $\{d, e\}$, B3: $\{c, e, f\}$, B4: $\emptyset$
• DB1: $\emptyset$, B2: $\{d, e, f\}$, B3: $\{a, b, c, e, f\}$, B4: $\emptyset$

Single correct

• ASymbol table is responsible for keeping track of the scope of variables.
• BSymbol table can be implemented using a binary search tree.
• CSymbol table is not required after the parsing phase.
• DSymbol table is created during the lexical analysis phase.

Single correct

• ARun-time function call management
• BRegister assignment to variables
• CStrength reduction
• DConstant folding

One or more correct

• AFor a production $A \to \epsilon$, $\epsilon$ will be added to $First(A)$.
• BIf there is any input right end marker, it will be added to $First(S)$, where $S$ is the start symbol.
• CFor a production $A \to \epsilon$, $\epsilon$ will be added to $Follow(A)$.
• DIf there is any input right end marker, it will be added to $Follow(S)$, where $S$ is the start symbol.

1001: i = 1
1002: j = 1
1003: t1 = 10*i
1004: t2 = t1+j
1005: t3 = 8*t2
1006: t4 = t3-88
1007: a[t4] = 0.0
1008: j = j+1
1009: if j <= 10 goto 1003
1010: i = i+1
1011: if i <= 10 goto 1002
1012: i = 1
1013: t5 = i-1
1014: t6 = 88*t5
1015: a[t6] = 1.0
1016: i = i+1
1017: if i <= 10 goto 1013

Numerical answer

Single correct

• AOnly (I) is correct.
• BOnly (II) is correct.
• CBoth (I) and (II) are correct.
• DNeither (I) nor (II) is correct.

Single correct

• ARule 1 is S-attributed and L-attributed; Rule 2 is S-attributed and not L-attributed; Rule 3 is neither S-attributed nor L-attributed
• BRule 1 is neither S-attributed nor L-attributed; Rule 2 is S-attributed and L-attributed; Rule 3 is S-attributed and L-attributed
• CRule 1 is neither S-attributed nor L-attributed; Rule 2 is not S-attributed and is L-attributed; Rule 3 is S-attributed and L-attributed
• DRule 1 is S-attributed and not L-attributed; Rule 2 is not S-attributed and is L-attributed; Rule 3 is S-attributed and L-attributed

Single correct

• A$G$ is neither LALR(1) nor SLR(1)
• B$G$ is CLR(1), not LALR(1)
• C$G$ is LALR(1), not SLR(1)
• D$G$ is LALR(1), also SLR(1)

One or more correct

• A$G_1$ is not $LL(1)$ and $G_2$ is $LL(1)$.
• B$G_1$ is $LL(1)$ and $G_2$ is not $LL(1)$.
• C$G_1$ and $G_2$ are not $LL(1)$.
• D$G_1$ and $G_2$ are ambiguous.

One or more correct

• AShift-reduce Parser
• BPredictive Parser
• CLL(1) Parser
• DLR Parser

Operator   Precedence   Associativity
   +       Highest      Left
   -       High         Right
   *       Medium       Right
   /       Low          Right

Numerical answer

S → DHTU      { S.val = D.val + H.val + T.val + U.val; }
D → "M" D1    { D.val = 5 + D1.val; }
D → ε         { D.val = −5; }
H → "L" H1    { H.val = 5 * 10 + H1.val; }
H → ε         { H.val = −10; }
T → "C" T1    { T.val = 5 * 100 + T1.val; }
T → ε         { T.val = −5; }
U → "K"       { U.val = 5; }

Single correct

• A45
• B50
• C55
• D65

Single correct

• A(1) $S \to Rf$ (2) $T \to \epsilon$ (3) $R \to cTR$
• B(1) $S \to fR$ (2) $T \to \epsilon$ (3) $R \to cTR$
• C(1) $S \to fR$ (2) $T \to cT$ (3) $R \to cR$
• D(1) $S \to Rf$ (2) $T \to cT$ (3) $R \to cR$