C Programming - Declarations and Initializations

1.
What is the output of the program given below ?
#include<stdio.h>
int main()
{
    enum status { pass, fail, atkt};
    enum status stud1, stud2, stud3;
    stud1 = pass;
    stud2 = atkt;
    stud3 = fail;
    printf("%d, %d, %d\n", stud1, stud2, stud3);
    return 0;
}
0, 1, 2
1, 2, 3
0, 2, 1
1, 3, 2
Answer: Option
Explanation:

enum takes the format like {0,1,2..) so pass=0, fail=1, atkt=2

stud1 = pass (value is 0)

stud2 = atkt (value is 2)

stud3 = fail (value is 1)

Hence it prints 0, 2, 1


2.
What will be the output of the program in 16 bit platform (Turbo C under DOS)?
#include<stdio.h>
int main()
{
    extern int i;
    i = 20;
    printf("%d\n", sizeof(i));
    return 0;
}
2
4
vary from compiler
Linker Error : Undefined symbol 'i'
Answer: Option
Explanation:
Linker Error : Undefined symbol 'i'
The statement extern int i specifies to the compiler that the memory for 'i' is allocated in some other program and that address will be given to the current program at the time of linking. But linker finds that no other variable of name 'i' is available in any other program with memory space allocated for it. Hence a linker error has occurred.

3.
What is the output of the program?
#include<stdio.h>
int main()
{
    extern int a;
    printf("%d\n", a);
    return 0;
}
int a=20;
20
0
Garbage Value
Error
Answer: Option
Explanation:

extern int a; indicates that the variable a is defined elsewhere, usually in a separate source code module.

printf("%d\n", a); it prints the value of local variable int a = 20. Because, whenever there is a conflict between local variable and global variable, local variable gets the highest priority. So it prints 20.


4.
What is the output of the program in Turbo C (in DOS 16-bit OS)?
#include<stdio.h>
int main()
{
    char *s1;
    char far *s2;
    char huge *s3;
    printf("%d, %d, %d\n", sizeof(s1), sizeof(s2), sizeof(s3));
    return 0;
}
2, 4, 6
4, 4, 2
2, 4, 4
2, 2, 2
Answer: Option
Explanation:

Any pointer size is 2 bytes. (only 16-bit offset)
So, char *s1 = 2 bytes.
So, char far *s2; = 4 bytes.
So, char huge *s3; = 4 bytes.
A far, huge pointer has two parts: a 16-bit segment value and a 16-bit offset value.

Since C is a compiler dependent language, it may give different output in other platforms. The above program works fine in Windows (TurboC), but error in Linux (GCC Compiler).


5.
What is the output of the program
#include<stdio.h>
int main()
{
    struct emp
    {
        char name[20];
        int age;
        float sal;
    };
    struct emp e = {"Tiger"};
    printf("%d, %f\n", e.age, e.sal);
    return 0;
}
0, 0.000000
Garbage values
Error
None of above
Answer: Option
Explanation:
When an automatic structure is partially initialized remaining elements are initialized to 0(zero).