GATE CS 2026 Set 2 — Question 19

MCQ+1 / -0.33EasyC ProgrammingProgramming & Data StructuresScoping (Static, Dynamic)Semantic AnalysisCompiler DesignStorage Classes

Compiler Design → C Programming → Scoping (Static, Dynamic)

Last updated 5 September 2026

Question

Consider the following three ANSI-C programs, P1, P2, and P3. P1 #include <stdio.h> int a=5; int main(){ int a=7; return(0); } P2 #include <stdio.h> int main(){ int a=5; int a=7; return(0); } P3 #include <stdio.h> int main(){ int a=5; float a=7; return(0); } Which one of the following statements is true?

Correct answer (A) Only P1 will compile without any error Solution P1 : This program declares a global variable int a = 5; and a local variable int a = 7; inside main . In C, a local variable can shadow a global variable with the same name. This is valid and will compile. P2 : This program declares int a = 5; and then attempts to redeclare int a = 7; within the same scope (the main function). Redeclaration of a variable in the same scope is not allowed in C. This will cause a compile-time error. P3 : This program declares int a = 5; and then attempts to declare float a = 7; in the same scope. Even though the types are different, the identifier a is already defined in this scope. This results in a conflicting types/redefinition error. This will cause a compile-time error. Therefore, only P1 compiles without error. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) Only P1 will compile without any error Solution P1 : This program declares a global variable int a = 5; and a local variable int a = 7; inside main . In C, a local variable can shadow a global variable with the same name. This is valid and will compile. P2 : This program declares int a = 5; and then attempts to redeclare int a = 7; within the same scope (the main function). Redeclaration of a variable in the same scope is not allowed in C. This will cause a compile-time error. P3 : This program declares int a = 5; and then attempts to declare float a = 7; in the same scope. Even though the types are different, the identifier a is already defined in this scope. This results in a conflicting types/redefinition error. This will cause a compile-time error. Therefore, only P1 compiles without error.

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