Decision making structures require that the programmer specify one or more conditions to be evaluated or tested by the program, along with a statement or statements to be executed if the condition is determined to be true, and optionally, other statements to be executed if the condition is determined to be false.
Following is the general form of a typical decision making structure found in most of the programming languages −
C++ programming language provides following types of decision making statements.
| Sr.No | Statement & Description |
|---|---|
| 1 | if statementAn ‘if’ statement consists of a boolean expression followed by one or more statements. |
| 2 | if…else statementAn ‘if’ statement can be followed by an optional ‘else’ statement, which executes when the boolean expression is false. |
| 3 | switch statementA ‘switch’ statement allows a variable to be tested for equality against a list of values. |
| 4 | nested if statementsYou can use one ‘if’ or ‘else if’ statement inside another ‘if’ or ‘else if’ statement(s). |
| 5 | nested switch statementsYou can use one ‘switch’ statement inside another ‘switch’ statement(s). |
The ? : Operator
We have covered conditional operator “? :” in previous chapter which can be used to replace if…else statements. It has the following general form −
Exp1 ? Exp2 : Exp3;
Exp1, Exp2, and Exp3 are expressions. Notice the use and placement of the colon.
The value of a ‘?’ expression is determined like this: Exp1 is evaluated. If it is true, then Exp2 is evaluated and becomes the value of the entire ‘?’ expression. If Exp1 is false, then Exp3 is evaluated and its value becomes the value of the expression.
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