GATE CS 2019 Set 1 — Question 37

MCQ+2 / -0.67MediumControl FlowC ProgrammingProgramming & Data StructuresStorage Classes

Programming & Data Structures → C Programming → Control Flow

Last updated 5 September 2026

Question

Consider the following C program: #include <stdio.h> int r(){ static int num=7; return num--; } int main(){ for (r();r();r()) printf("%d",r()); return 0; } Which one of the following values will be displayed on execution of the programs?

Correct answer (B) 52 Solution The function r() contains a static variable num initialized to 7. It returns the current value of num and then decrements it (post-decrement). Calls to r() return: 7, 6, 5, 4, 3, 2, 1, 0, -1, ... The for loop structure is for (initialization; condition; increment) body . Execution trace: 1. Initialization : r() is called. Returns 7. num becomes 6. 2. Condition : r() is called. Returns 6. num becomes 5. Condition (6) is true (non-zero). 3. Body : printf("%d", r()) is executed. r() is called. Returns 5. num becomes 4. Prints 5 . 4. Increment : r() is called. Returns 4. num becomes 3. 5. Condition : r() is called. Returns 3. num becomes 2. Condition (3) is true. 6. Body : printf("%d", r()) is executed. r() is called. Returns 2. num becomes 1. Prints 2 . 7. Increment : r() is called. Returns 1. num becomes 0. 8. Condition : r() is called. Returns 0. num becomes -1. Condition (0) is false. 9. Loop terminates. The output is 52 . Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (B) 52 Solution The function r() contains a static variable num initialized to 7. It returns the current value of num and then decrements it (post-decrement). Calls to r() return: 7, 6, 5, 4, 3, 2, 1, 0, -1, ... The for loop structure is for (initialization; condition; increment) body . Execution trace: 1. Initialization : r() is called. Returns 7. num becomes 6. 2. Condition : r() is called. Returns 6. num becomes 5. Condition (6) is true (non-zero). 3. Body : printf("%d", r()) is executed. r() is called. Returns 5. num becomes 4. Prints 5 . 4. Increment : r() is called. Returns 4. num becomes 3. 5. Condition : r() is called. Returns 3. num becomes 2. Condition (3) is true. 6. Body : printf("%d", r()) is executed. r() is called. Returns 2. num becomes 1. Prints 2 . 7. Increment : r() is called. Returns 1. num becomes 0. 8. Condition : r() is called. Returns 0. num becomes -1. Condition (0) is false. 9. Loop terminates. The output is 52 .

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