Output of C programs | Set 46

QUE.1 What would be output following C program? C

#include <stdio.h>
int main()
{
    char* str = "IncludeHelp";
    printf("%c\n", *&*str);
    return 0;
}

OPTION a) Error b) IncludeHelp c) I d)*I

 Answer: c

Explanation : & is a reference operator, * is de-reference operator. We can use these operators any number of times. str points the first character of IncludeHelp, *str points "I", * & again reference and de-reference the value of str. QUE.2 What would be output following C program? C

#include <stdio.h>
int main()
{
    int iVal;
    char cVal;
    // void pointer
    void* ptr;
    iVal = 50;
    cVal = 65;

    ptr = &iVal;
    printf("value =%d, size= %d\n", *(int*)ptr, sizeof(ptr));

    ptr = &cVal;
    printf("value =%d, size= %d\n", *(char*)ptr, sizeof(ptr));
    return 0;
}

OPTION a) Error b) value =50, size= 4 value =65, size= 4 c) value =50, size= 4 value =65, size= 1 d)Garbage Values

Answer: b

Explanation : void pointer can be type casted to any type of data type, and pointer takes 4 bytes (On 32 bit compiler). To print value using void pointer, you will have to write like this *(data_type*)void_ptr;. QUE.3 What would be output following C program? C

#include <stdio.h>
int main()
{
    char ch = 10;
    void* ptr = &ch;
    printf("%d, %d", *(char*)ptr, ++(*(char*)ptr));
    return 0;
}

OPTION a) 11, 11 b) 10, 11 c) ERROR d) 10, 10

Answer: a

Explanation : *(char*)ptr will return the value of ch, since we know printf evaluates right to left. So, ++(*(char*)ptr) will increase the value to 11. QUE.4 What is the output of the following C program? C

#include <stdio.h>
int main()
{
    int a = 10, b = 2;
    int* pa = &a, *pb = &b;
    printf("value = %d", *pa/*pb);
    return 0;
}

OPTION a) 5 b) 5.0 c) ERROR d) None of these

Answer:c

Explanation : ERROR: unexpected end of file found in comment. The compiler is treated the operator / and * as /*, that happens to be the starting of comment. To fix the error, use either *pa/ *pb (space between operators) or *pa/(*pb). QUE.5 What is the output of the following C program? C

#include <stdio.h>

int main()
{
    int a = 10;
    int b = 2;
    int c;

    c = (a & b);
    printf("c= %d", c);

    return 0;
}

OPTION a) c= 12 b) c= 10 c) c= 2 d) c= 0

Answer:c

Explanation : Bitwise AND (&) operator copies bit(s), if there exist both of the operands. Here, binary of a is "1010" and binary of b is "0010". Thus, result of expression (a & b) is "0010" which is equivalent to 2 in Decimal.