250+ TOP MCQs on External Variables and Answers [2024]

C questions and puzzles on “External Variables”. One shall practice these questions and puzzles to improve their C programming skills needed for various interviews (campus interviews, walkin interviews, company interviews), placements, entrance exams and other competitive exams. These programming puzzles can be attempted by anyone focusing on learning C Programming language. They can be a beginner, fresher, engineering graduate or an experienced IT professional. Our C questions come with detailed explanation of the answers which helps in better understanding of C concepts.

Here is a listing of C questions and puzzles on “External Variables” along with answers, explanations and/or solutions:

1. What will be the output of the following C code?

```
    #include 
```
```
    void main()
```
```
    {
```
```
        m();
```
```
        printf("%d", x);
```
```
    }
```
```
    int x;
```
```
    void m()
```
```
    {
```
```
        x = 4;
```
```
    }
```

a) 4
b) Compile time error
c) 0
d) Undefined
Answer: b
Clarification: None.

2. What will be the output of the following C code?

```
    #include 
```
```
    int x;
```
```
    void main()
```
```
    {
```
```
        printf("%d", x);
```
```
    }
```

a) Junk value
b) Run time error
c) 0
d) Undefined
Answer: c
Clarification: None.

3. What will be the output of the following C code?

```
    #include 
```
```
    int x = 5;
```
```
    void main()
```
```
    {
```
```
        int x = 3;
```
```
        printf("%d", x);
```
```
        {
```
```
            x = 4;
```
```
        }
```
```
        printf("%d", x);
```
```
    }
```

a) Run time error
b) 3 3
c) 3 5
d) 3 4
Answer: d
Clarification: None.

4. What will be the output of the following C code?

```
    #include 
```
```
    int x = 5;
```
```
    void main()
```
```
    {
```
```
        int x = 3;
```
```
        printf("%d", x);
```
```
        {
```
```
            int x = 4;
```
```
        }
```
```
        printf("%d", x);
```
```
    }
```

a) 3 3
b) 3 4
c) 3 5
d) Run time error
Answer: a
Clarification: None.

5. Functions in C are always _________
a) Internal
b) External
c) Both Internal and External
d) External and Internal are not valid terms for functions
Answer: b
Clarification: None.

6. Global variables are ____________
a) Internal
b) External
c) Both Internal and External
d) None of the mentioned
Answer: b
Clarification: None.

7. Which of the following is an external variable in the following C code?

```
    #include 
```
```
    int func (int a)
```
```
    {
```
```
        int b;
```
```
        return b;
```
```
    }
```
```
    int main()
```
```
    {
```
```
        int c;
```
```
        func (c);
```
```
    }
```
```
    int d;
```

a) a
b) b
c) c
d) d
Answer: d
Clarification: None.

8. What will be the output of the following C code?

```
     #include 
```
```
    int main()
```
```
    {
```
```
        printf("%d", d++);
```
```
    }
```
```
    int d = 10;
```

a) 9
b) 10
c) 11
d) Compile time error
Answer: d
Clarification: None.

9. What will be the output of the following C code?

```
    #include 
```
```
    double var = 8;
```
```
    int main()
```
```
    {
```
```
        int var = 5;
```
```
        printf("%d", var);
```
```
    }
```

a) 5
b) 8
c) Compile time error due to wrong format identifier for double
d) Compile time error due to redeclaration of variable with same name
Answer: a
Clarification: None.

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