Data types and size in c program

1. Comment on the output of this C code?

1.     #include <stdio.h>

2.     int main()

3.     {

4.         int a[5] = {1, 2, 3, 4, 5};

5.         int i;

6.         for (i = 0; i < 5; i++)

7.             if ((char)a[i] == '5')

8.                 printf("%d\n", a[i]);

9.             else

10.                 printf("FAIL\n");

11.     }

a) The compiler will flag an error
b) Program will compile and print the output 5
c) Program will compile and print the ASCII value of 5
d) Program will compile and print FAIL for 5 times
View Answer

Answer: d
Explanation: The ASCII value of 5 is 53, the char type-casted integral value 5 is 5 only.
Output:
$ cc pgm1.c
$ a.out
FAILED
FAILED
FAILED
FAILED
FAILED

2. The format identifier ‘%i’ is also used for _____ data type?
a) char
b) int
c) float
d) double
View Answer

Answer: b
Explanation: Both %d and %i can be used as a format identifier for int data type.

3. Which data type is most suitable for storing a number 65000 in a 32-bit system?
a) signed short
b) unsigned short
c) long
d) int
View Answer

Answer: b
Explanation: 65000 comes in the range of short (16-bit) which occupies the least memory. Signed short ranges from -32768 to 32767 and hence we should use unsigned short.

4. Which of the following is a User-defined data type?
a) typedef int Boolean;
b) typedef enum {Mon, Tue, Wed, Thu, Fri} Workdays;
c) struct {char name[10], int age};
d) all of the mentioned
View Answer

Answer: d
Explanation: typedef and struct are used to define user-defined data types.

5. What is the size of an int data type?
a) 4 Bytes
b) 8 Bytes
c) Depends on the system/compiler
d) Cannot be determined
View Answer

Answer: c
Explanation: The size of the data types depend on the system.

6. What is the output of this C code?

1.     #include  <stdio.h>

2.     int main()

3.     {

4.        signed char chr;

5.        chr = 128;

6.        printf("%d\n", chr);

7.        return 0;

8.     }

a) 128
b) -128
c) Depends on the compiler
d) None of the mentioned
View Answer

Answer: b
Explanation: signed char will be a negative number.
Output:
$ cc pgm2.c
$ a.out
-128

7. Comment on the output of this C code?

1.     #include  <stdio.h>

2.     int main()

3.     {

4.         char c;

5.         int i = 0;

6.         FILE *file;

7.         file = fopen("test.txt", "w+");

8.         fprintf(file, "%c", 'a');

9.         fprintf(file, "%c", -1);

10.         fprintf(file, "%c", 'b');

11.         fclose(file);

12.         file = fopen("test.txt", "r");

13.         while ((c = fgetc(file)) !=  -1)

14.             printf("%c", c);

15.         return 0;

16.     }

a) a
b) Infinite loop
c) Depends on what fgetc returns
d) Depends on the compiler
View Answer

Answer: a
Explanation: None.
Output:
$ cc pgm3.c
$ a.out
a

8. What is short int in C programming?
a) Basic datatype of C
b) Qualifier
c) Short is the qualifier and int is the basic datatype
d) All of the mentioned
View Answer

Answer: c
Explanation: None.