Question

^{\prime}\right)\( cout \)<… # What is the output of the following statements? a. if \(\left(^{\prime} R^{\prime}<^{\prime} \$^{\prime} \& \&^{\prime} \&^{\prime}<=^{\prime} \\#^{\prime}\right)\) cout \(<<\) " \(\$$ # \)"\(; cout \)<<\( " \)R \&^{\prime \prime}\(; cout \)<<$ endl b. if ('4' > '3' || 2 < -10) cout << "1 2 3 4" << endl; cout << "$$" << endl; c. if ("Jack" <= "John" && "Business" >= "Accounting") cout << "Jack Accounting" << endl; cout << "John Business" << endl;

Short answer

Outputs are: a) R \&, b) 1 2 3 4 and $$, c) John Business.

Step-by-step solution

Evaluate Condition in Statement a

Examine the condition \('R'<'\(' && '&'<= '#'\). In ASCII, characters are compared by their numerical codes. Here, the value for \('\)'\) is 36 and \('R'\) is 82, so \('R' < '$'\) is false. The value for \('&'\) is 38 and \('#'\) is 35, so \('&' <= '#'\) is also false. As the AND condition requires both to be true, the overall condition evaluates to false.

Output for Statement a

Since the condition in statement a is false, the code inside the if block \(\text{cout << "$$ #"};\) is not executed. Then, \(\text{cout << "R \&";}\) is executed separately, which outputs \(R \&\), and the next statement outputs a newline.

Evaluate Condition in Statement b

Consider the condition \('4' > '3' || 2 < -10\). The ASCII value of \('4'\) is 52, and \('3'\) is 51, so \('4' > '3'\) evaluates to true. The condition \(2 < -10\) is false. Since it's an OR condition, only one needs to be true for the whole condition to be true.

Output for Statement b

Given the condition is true, the code \(\text{cout << "1 2 3 4" << endl;}\) is executed, printing \(1 2 3 4\) followed by a newline. Additionally, as it's outside of the conditional block, \(\text{cout << "$$" << endl;}\) is also executed, printing \(\$$\) followed by a newline.

Evaluate Condition in Statement c

Examine the condition \(\text{"Jack" <= "John" && "Business" >= "Accounting"}\). With string comparison, the first letter is compared alphabetically. \(\text{"Jack"}\) is less than \(\text{"John"}\) because 'a' comes before 'o'. Conversely, \(\text{"Business"}\) does not come before \(\text{"Accounting"}\), meaning it's false. The AND condition therefore is false.

Output for Statement c

Since the condition is false, the block inside the if is not executed, so \(\text{cout << "Jack Accounting" << endl;}\) does not run. The next statement \(\text{cout << "John Business" << endl;}\) runs regardless, printing \(\text{"John Business"}\) followed by a newline.

Key concepts

ASCII Character Comparison

In C++, ASCII character comparison is used to compare characters based on their numeric ASCII values. Each character has a corresponding ASCII code, which is an integer number. For example, the character \('R'\) corresponds to 82, while \('\('\) corresponds to 36. This means that \('R'\) is numerically greater than \('\)'\).
In expressions such as \('R' < '\('\), the comparison is made using these ASCII values. Since the ASCII value of 'R' is greater than the ASCII value of '\)', the condition evaluates to false. Similarly, comparisons between special characters such as \('&'\) and \('#'\) rely on their ASCII values, 38 and 35, respectively.
Understanding ASCII character comparison is essential, as it often forms the basis for conditional checks in C++ programming involving character data types. When you compare characters, knowing the sequence of ASCII values will tell you which characters are smaller or larger according to C++ conventions.

String Comparison in C++

String comparison in C++ is similar to character comparison but involves comparing sequences of characters. In C++, strings are compared lexicographically, meaning they are compared based on dictionary order. This occurs character by character from left to right.
For instance, when comparing \("Jack" <= "John"\), C++ first compares the first character 'J' in both strings, as they match, it moves to the next character. The second character 'a' in "Jack" is alphabetically less than 'o' in "John", therefore, this part of the condition is true. However, string comparison doesn't always involve only the first mismatch, otherwise, this understanding would be correct.
String comparison can be tricky because it involves evaluating each character's ASCII value in order, just as is done for individual characters. Knowing how to compare strings correctly can prevent logical errors in your programs and aids in constructing effective control flows.

Output Statements in C++

Output statements in C++ are constructed primarily using the \(cout\) object. It is part of the iostream library and allows developers to print to the standard output, typically the console.
The syntax used for output starts with \(cout <<\), followed by the data or string you want to display. For example, \(cout << "Hello, World!";\) will print the phrase "Hello, World!" on the screen.
One important aspect of using \(cout\) is controlling the flow of output. The \(endl\) manipulator is frequently used to insert a newline, ensuring that the subsequent output starts on the next line. This is very handy for formatting text to make it more readable on the console.
Understanding how to effectively use \(cout\) and various output manipulators like \(endl\), combined with control structures, is vital for communicating results and debugging programs effectively in C++.