NaimExplain

What is the value assigned to the variable in each of these cases? Explain curious results. Be careful! int x, y; a) x = 1/2; b) y = 3.0/2.0; double z, w, t; c) z = 1/2; d) w = 3/2; e) t = 3.0/2.0; Answer: a) 0 is assigned.1/2 is computed using truncating integer divide which gives 0. b) 1.5 is calculated and assigned. The fractional part is discarded; 1 is stored. c) 0 is calculated because 1/2 is done with truncating integer divide, gives 0. The floating point value 0.0 is stored. d) 1 is calculated, because truncating int divide, 1.0 is stored e) 1.5 is calculated and stored.

When you use a double, what is doubled? When you use a long int, how much longer is the long int than an int? Comment. Answer: In a double, the precision part of the value is about twice the precision of a float. The size of the exponent is also increased. In most implementations, long is the same size as int.

Write a short program that contains statements to output the values of a variable that you define but neither initialize nor assign. Discuss the output you get.  Answer: #include <iostream> using namespace std; int main() {   int uninitialized;   cout << uninitialized << endl;   return 0; }

Give the declaration for two variables, feet and inches. Declare each to be of type int, and both initialized to zero in the declaration. Give both initialization alternatives. Answer: int feet = 0; int inches = 0; //Alternate initialization. int feet (0); int inches(0);

 What is the difference between a warning from the compiler and an error message from the compiler? Answer: An error message usually causes code generation to stop. A warning does not. Unless you understand what the warning is all about you should not ignore warnings.

What does the line #include <iostream> do for your program? Answer: The #include directive provides declarations and definitions of the iostream components so that your program can use them in a way that allows the system linker to connect your program to the corresponding library.

Given the C++ output statements. What is the output of these lines of code? Explain.  cout << "If you have "; cout << "a number of pods "; cout << "you can quit."; cout << "\n"; Answer: If you have a number of pods you can quit. Explanation: Note that there is a <cr> emitted by the code, which puts the next output position on the next line at the left end.

Write a C++ program that outputs "My first C++ program" and then outputs a carriage return. Answer: #include <iostream> using namespace std; int main() {   cout << “My first C++ program” << endl; } Explanation: An alternative is to place using namespace std; after the #include directive, or to place this inside the block of the function main. This depends on the local rules for placing namespace directives and definitions.

In the history of the C++ language, what was the immediate predecessor of the C++ language? How is this older language related to C++? Answer: The immediate predecessor of C++ is the C programming language. C is very nearly a proper subset of C++.