Interest paid = 25914 Total = 149314 Press Enter to terminate in C#

Print USS Code 128 in C# Interest paid = 25914 Total = 149314 Press Enter to terminate

Executing the program with illegal input generates the following output:

Enter principal:1234 Enter interest:-125 Interest cannot be negative Principal Interest = 1234 = 0%

Indent the lines within an if clause to enhance readability C# ignores such indentation, but it helps us humans Most programming editors support autoindenting, whereby the editor automatically indents as soon as you enter the if command To set auto-indenting in Visual Studio, choose Tools Options Then expand the Text Editor node From there, expand C# Finally, click Tabs On this page, enable Smart Indenting and set the number of spaces per indent to your preference I use two spaces per indent for this book Set the Tab Size to the same value

Some functions must check for mutually exclusive conditions For example, the following code segment stores the maximum of two numbers, a and b, in the variable max:

// store the maximum of int max; // if a is greater than if (a > b) { // save off a max = a; } // if a is less than or if (a <= b) { // save off b max = b; } a and b into the variable max b

The second if statement is needless processing because the two conditions are mutually exclusive If a is greater than b, a can t possibly be less than or equal to b C# defines an else clause for just this case The else keyword defines a block of code that s executed if the if block is not The code segment to calculate the maximum now appears as follows:

// store the maximum of int max; // if a is greater than if (a > b) { // save off a max = a; } else { // save off b max = b; } a and b into the variable max b

If a is greater than b, the first block is executed; otherwise, the second block is executed In the end, max contains the greater of a or b

Sequences of else clauses can get confusing Some programmers, myself included, like to avoid them when doing so doesn t cause even more confusion You could write the maximum calculation like this:

// store the maximum of a and b into the variable max int max; // start by assuming that a is greater than b max = a;

// if it is not if (b > a) { // then you can change your mind max = b; }

Some programmers avoid this style like the plague, and I can sympathize That doesn t mean I m going to change; it just means I sympathize You see both this style and the else style in common use

The CalculateInterest program warns the user of illegal input; however, continuing with the interest calculation, even if one of the values is illogical, doesn t seem quite right It causes no real harm here because the interest calculation takes little or no time and the user can ignore the results, but some calculations aren t nearly so quick In addition, why ask the user for an interest rate after she has already entered an invalid value for the principal The user knows that the results of the calculation will be invalid no matter what she enters next The program should only ask the user for an interest rate if the principal is reasonable and only perform the interest calculation if both values are valid To accomplish this, you need two if statements, one within the other An if statement found within the body of another if statement is called an embedded or nested statement The following program, CalculateInterestWithEmbeddedTest, uses embedded if statements to avoid stupid questions if a problem with the input is detected:

// CalculateInterestWithEmbeddedTest // calculate the interest amount // paid on a given principal If either // the principal or the interest rate is // negative, then generate an error message // and don t proceed with the calculation using System; namespace CalculateInterestWithEmbeddedTest { public class Program { public static void Main(string[] args) { // define a maximum interest rate int nMaximumInterest = 50;