Predict the output of the following C++ programs:

• Question 1:
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  #include <cstdlib> #include <iostream> using namespace std; int main() {     int ran = rand();     cout << ran << endl;     return 0; }

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  Output:

  1804289383
  

  Explanation: As the declared number is an integer, It will produce the random number from 0 to RAND_MAX. The value of RAND_MAX is library-dependent but is guaranteed to be at least 32767 on any standard library implementation.

• Question 2:
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  #include <cstdlib> #include <iostream> using namespace std;    int main() {     cout << RAND_MAX << endl;     return 0; }

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  Output:

  2147483647
  

  Explanation: The output is Compiler Dependent. RAND_MAX is a function used by the compiler to create a maximum random number.

• Question 3:
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  #include <iostream> using namespace std; int main() {     void a = 10, b = 10;     int c;     c = a + b;     cout << c;     return 0; }

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  Output:

  Compile time error
  

  Explanation: void will not accept any values to its type.

• Question 4:
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  #include <iostream>    using namespace std;    int array1[] = { 1200, 200, 2300, 1230, 1543 }; int array2[] = { 12, 14, 16, 18, 20 }; int temp, result = 0; int main() {     for (temp = 0; temp < 5; temp++) {         result += array1[temp];     }     for (temp = 0; temp < 5; temp++) {         result += array2[temp];     }     cout << result;     return 0; }

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  Output:

  
  
  
  

  6553
  

  Explanation: In this program we are adding the every element of two arrays. All the elements of array1[] and array2[] will be added and the sum will be stored in result and hence output is 6553.

• Question 5:
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  #include <iostream> using namespace std; int main() {     int a = 5, b = 10, c = 15;     int arr[3] = { &a;, &b;, &c; };     cout << *arr[*arr[1] - 8];     return 0; }

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  Output:

  Compile time error!
  

  Explanation: The conversion is invalid in this array. The array arr[] is declared to hold integer type value but we are trying to assign references(addresses) to the array so it will arise error. The following compilation error will be raised:

  cannot convert from ‘int *’ to ‘int’

• Question 6:
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  #include <iostream> using namespace std; int main() {     int array[] = { 10, 20, 30 };     cout << -2 [array];     return 0; }

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  Output:

  -30
  

  Explanation: -2[array]: this statement is equivalent to -(array[2]). At the zero index 30 is stored hence negation of 30 will be printed due to unary operator (-).

• Question 7:
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  #include <iostream> using namespace std; int main() {     int const p = 5;     cout << ++p;     return 0; }

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  Output:

  Compile time Error!
  

  Explanation: Constant variables are those whose value can’t be changed throughout the execution. ++p statement try to change the value hence compiler will raise an error.

• Question 8:
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  #include <iostream> using namespace std; int main() {     char arr[20];     int i;     for (i = 0; i < 10; i++)         *(arr + i) = 65 + i;     *(arr + i) = '\0';     cout << arr;     return (0); }

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  Output:

  ABCDEFGHIJ
  

  Explanation: Each time we are assigning 65 + i. In first iteration i = 0 and 65 is assigned. So it will print from A to J.

• Quesion 9:
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  #include <iostream> using namespace std; int Add(int X, int Y, int Z) {     return X + Y; } double Add(double X, double Y, double Z) {     return X + Y; } int main() {     cout << Add(5, 6);     cout << Add(5.5, 6.6);     return 0; }

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  Output:

  Compile time error!
  

  Explanation: Here we want to add two element but in the given functions we take 3 argumants.So compiler doesn’t get the reqired function(function with 2 arguments)

• Question 10:
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  #include <iostream> using namespace std; #define PR(id) cout << "The value of " #id " is " << id int main() {     int i = 10;     PR(i);     return 0; }

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  Output:

  The value of i is 10
  

  Explanation: In this program, we are just printing the declared value through a macro. Carefully observe that in macro there is no semicolon(;) used as a termination statement.

This article is contributed by Avinash Kumar Singh email: avinash.sing.inbox@gmail.com. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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