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Output of C Programs | Set 14
• Difficulty Level : Medium
• Last Updated : 06 Jul, 2018

Predict the output of below C programs.

Question 1

 `#include``int` `main()``{``   ``int` `a;``   ``char` `*x;``   ``x = (``char` `*) &a;``   ``a = 512;``   ``x = 1;``   ``x = 2;``   ``printf``(``"%d\n"``,a);`` ` `   ``getchar``();``   ``return` `0;``} `

Answer: The output is dependent on endianness of a machine. Output is 513 in a little endian machine and 258 in a big endian machine.

Let integers are stored using 16 bits. In a little endian machine, when we do x = 1 and x = 2, the number a is changed to 00000001 00000010 which is representation of 513 in a little endian machine. The output would be same for 32 bit numbers also.

In a big endian machine, when we do x = 1 and x = 2, the number is changed to 00000001 00000010 which is representation of 258 in a big endian machine.

Question 2

 `int` `main()``{``  ``int` `f = 0, g = 1;``  ``int` `i;``  ``for``(i = 0; i < 15; i++) ``  ``{``    ``printf``(``"%d \n"``, f);``    ``f = f + g;``    ``g = f - g;``  ``}``  ``getchar``();``  ``return` `0;``}`

Answer: The function prints first 15 Fibonacci Numbers.

Question 3
Explain functionality of following function.

 `int` `func(``int` `i)``{``  ``if``(i%2) ``return` `(i++);``  ``else` `return` `func(func(i-1));``}`

Answer: If n is odd then returns n, else returns (n-1). So if n is 12 then we get and if n is 11 then we get 11.