GATE CSE 2010 | Question: 44

Question

The following program is to be tested for statement coverage:

begin
    if (a==b) {S1; exit;}
    else if (c==d) {S2;}
        else {S3; exit;}
    S4;
end

The test cases T1, T2, T3 and T4 given below are expressed in terms of the properties satisfied by the values of variables $a,\:b,\:c$ and $d$. The exact values are not given.

T1: a, b, c and d are all equal

T2: a, b, c and d are all distinct

T3: a = b and c != d

T4: a != b and c = d

Which of the test suites given below ensures coverage of statements S1, S2, S3 and S4?

• A. T1, T2, T3
• B. T2, T4
• C. T3, T4
• D. T1, T2, T4

Comments

Out of syllabus

Answer 1

T1 covers S1

T2 covers S3

T3 covers S1

T4 covers S2, S4

so inorder to cover all 4 either T1,T2, T4 or  T2, T3 , T4

option D

Comments

How does T1 cover S1? T1 is saying a,b,c,d all are equal but S1 will be executed when a==b and then it will exit the main program, so how is it ensuring that c is also equal to d?

---

It is a test case where all variable are equal. The execution of the program gets "short-circuited" at the condition 

a==b

so it covers statement S1 and exits. We are not checking the test cases themselves, but we are checking the coverage of the test cases.

Answer 2

#include <stdio.h>
#include <stdlib.h>
void main(){
	int a=2;
	int b=3;
	int c=4;
	int d=4;

	if(a==b){
		printf("a is equal to b\n");exit;
	}
	else if(c==d){
		printf("b is equal to d\n");exit;
	}
	else 
		printf("b is not equal to d\n");exit;

	printf("s4 case\n");
}

This is code you can change values appropriately and get the answer.

T1 covers: s1,s4

T2 covers: s3,s4

T3 covers: s1,s4

T1 covers: s2,s4

Ans: D. T1, T2, T3

Answer 3

T2 is essential because it is the only statement covering S4, eliminate option (c)

S2 can be covered by T4 only

now condition a==b leading to S1 can be satisfied by T1 only.

Answer : (d)

Comments

T2 is not covering s4 pls review again it can cover only S3 bcoz exit keyword is there which is used for leaving the main program .

Answer 4

To achieve statement coverage, we need to ensure that all statements (S1, S2, S3, and S4) are executed at least once by the test cases. Let's analyze each test case to check which statements are executed:

Program logic breakdown:

1. If (a == b):

   • If true, S1 is executed, and the program exits.
   • If false, the second condition if (c == d) is checked.

2. If (c == d) (executed when a != b):

   • If true, S2 is executed.
   • If false, S3 is executed, and the program exits.

3. After S2 (if c == d is true), the program moves to S4.

Test case analysis:

• T1: a == b, c == d (i.e., a, b, c, d are all equal)

  • The first condition a == b is true, so S1 is executed, and the program exits. (Only S1 is covered.)

• T2: a != b, c != d (i.e., a, b, c, d are all distinct)

  • The first condition a == b is false, so it checks c == d.
  • The second condition c == d is also false, so S3 is executed, and the program exits. (Only S3 is covered.)

• T3: a == b, c != d

  • The first condition a == b is true, so S1 is executed, and the program exits. (Only S1 is covered.)

• T4: a != b, c == d

  • The first condition a == b is false, so it checks c == d.
  • The second condition c == d is true, so S2 is executed, followed by S4. (S2 and S4 are covered.)

Test Suite Analysis:

• Option (a) T1, T2, T3:

  • T1: covers S1.
  • T2: covers S3.
  • T3: covers S1 again (redundant).
  • This suite does not cover S2 or S4.

• Option (b) T2, T4:

  • T2: covers S3.
  • T4: covers S2 and S4.
  • This suite does not cover S1.

• Option (c) T3, T4:

  • T3: covers S1.
  • T4: covers S2 and S4.
  • This suite does not cover S3.

• Option (d) T1, T2, T4:

  • T1: covers S1.
  • T2: covers S3.
  • T4: covers S2 and S4.
  • This suite covers all statements: S1, S2, S3, and S4.

Correct Answer:

(d) T1, T2, T4 ensures coverage of all statements (S1, S2, S3, and S4).

Answer 5

https://www.youtube.com/watch?v=BTFPPBGw5DU

Comments

question is different

Answer 6

For condition if(a == b)

T1 is valid as it's just asking if a == b

For condition elseif(c==d)

T4 is valid as elseif only executes if previous if condition was false so a!=b and c==d

For condition else

T2 is valid as neither a==b not c==d