During coding, you tackle most of the situations where your next move depends on your decisions. Now to make such a decision in programming, we use the decision-making statement provided by the programming language.
Decision-Making statements are used when a user wants a certain block to be executed under certain conditions. The condition to be checked is determined by true or false value.
C++ programming language provides the following types of decision-making statements:
- if statement
- if-else statement
- nested-if statement
- if-else-if ladder statement
- switch-case statement
The above decision making statements determines the direction of flow of the program execution.
C++ if statement
An if statement consists of a Boolean expression followed by one or more statements. If the Boolean expression is true, the block of code inside the if statement will be executed else not. This is most simple of all the decision making statements.
The syntax of the if statement in C++:
1 2 3 4 | if (condition) { //block of statement } |
- If the condition is evaluated true, block of statement is executed.
- If the condition is evaluated false, block of statement is skipped.
For example and flowchart of C++ if statement, click here
C++ if…else statement
If the Boolean expression is true then the code inside the if statement block is executed or if it is false then the code inside else statement will be executed. Hence if..else statement.
The syntax of the if..else statement in C++:
1 2 3 4 5 6 7 8 | if (condition) { //code executed if condition true } else { //code executed if condition false } |
For example and flowchart C++ if…else statement, click here
C++ nested if statement
This statement allows the user to use if block inside the other if block. And the inner if statement is executed only if the outer if statement’s condition is true.
The syntax of the nested if statement in C++:
1 2 3 4 5 6 7 8 | if(condition1) { //block of code to be executed if(condition2) { //block of code to be executed } } |
You can also nest the if..else statement in same manner as shown below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | //Nested if....else statement if(condition1) { if(condition2) { //block of statement; } else { //block of statement; } } else { //block of statement; } |
For example and flowchart C++ nested if statement, click here
C++ if-else-if ladder statement
This statement allows the user to have multiple options to check for different conditions. Here, if one of the if or else-if condition is true then that part of the code will be executed and the rest will be skipped. if none of the conditions are true then the final else statement present at the end will be executed.
The syntax of the if-else-if ladder statement in C++:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | if(condition1) { //code to be executed if condition1 is true } else if(condition2){ //code to be executed if condition2 is true } else if(condition3){ //code to be executed if condition3 is true } ... else{ //final else if all the above condition are false } |
For example and flowchart C++ if-else-if ladder statement, click here
C++ switch statement
A switch statement allows a variable to be tested for equality against multiple values and each of those values is called a case. It can be used instead of nested if...else..if ladder.
Switch expression and case value must be of the same type. There must be at least one case or multiple cases with unique case values. In the end, it can have a default case which is optional that is executed if no cases are matched.
The syntax of the switch statement statement in C++:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | switch (expression) { case value1: //code to be executed; break; //optional case value2: //code to be executed; break; //optional . . . . case valueN: //code to be executed; break; //optional default: code to be executed if all cases are not matched; } |
The expression is evaluated once and compared with the values of each case label.
- If the expression and case value are matched then the corresponding code present within that particular case will be executed and a break statement is used to come out of the switch statement by skipping all of the other cases.
- If the values of expression and case do not match, the code within
default:is executed.
For example and flowchart C++ switch statement statement, click here
The ? : Operator
? : This operator is called a conditional operator or ternary operator. The execution of this operator depends on the result of the binary condition.
Ternary Operator can also be used instead of if...else statement as it does follow the same algorithm and the only difference is ternary operator takes less space and it’s the short version of if...else statement.
? : Operator is also called Ternary Operator because it takes three operands to operate, as shown in the syntax below.
Syntax of Ternary Operator:
1 | variable = Condition ? Expression1 : Expression1 |
Here, the condition that is the binary condition is to be evaluated. And if the binary condition is true then Expression1 is executed and if it is false then Expression2 is executed. And both of them return the results.
Click here to learn about ternary operator with an example.