# 3i Infotech Papers: Sample Questions 710 - 711 of 1245

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## Question number: 710

Essay Question▾

### Describe in Detail

What is the minimum and maximum length of the header in the TCP segment and IP datagram?

### Explanation

• The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.

• TCP provides reliable data delivery with the help of sequencing and checksums.

• 32 Bit number is used for byte level numbering of TCP segments.

• Data Offset field- 4 Bit field shows the number of 32 Bit words in the header

• The minimum size header is 5 words.

• Packet format of data recognized by IP is called IP datagram.

• Consists of two components: the header and data, which need to be transmitted.

• The size of the Header Length or the IHL field is 4 bits- specifies the length of header, which can range from 20 to 60 bytes.

• IP datagram has a fixed header size except for the IP Options field- which can be 20–60 bytes.

## Question number: 711

Essay Question▾

### Describe in Detail

What is the output of the following program?

1. `# include <stdio.h>`
2. `int aaa () { printf ( “hi” ); }`
3. `int bbb () { printf ( “hello” ); }`
4. `int ccc () { printf ( “bye” ); }`
5. `main ()`
6. `{`
7. `    int ( * ptr[3]) ();`
8. `    ptr[0] = aaa;`
9. `    ptr[1] = bbb;`
10. `    ptr[2] = ccc;`
11. `    ptr[2] ();`
12. `}`

### Explanation

In the program

 int aaa () {printf (“hi”); } Define the integer function aaa () int bbb () {printf (“hello”); } Define the integer function bbb () int ccc () {printf (“bye”); } Define the integer function ccc () int (* ptr [3] ) (); int (* ptr [3] ) () says that ptr is an array of pointers to functions that takes no arguments and returns the type int. ptr [0] = aaa; First function pointer in the array is initialized with the address of the function aaa. ptr [1] = bbb; Second function pointer in the array is initialized with the address of the function bbb. ptr [2] = ccc; Third function pointer in the array is initialized with the address of the function ccc. ptr [2] (); The call to the function ptr [2] () is same as calling ccc () So, it results in printing “bye”.