Decision Making in C++ helps to write decision-driven statements and execute a particular set of code based on certain conditions.
The if statement alone tells us that if a condition is true it will execute a block of statements and if the condition is false it won’t. But what if we want to do something else if the condition is false. Here comes the C++ else statement. We can use the else statement with if statement to execute a block of code when the condition is false.
Syntax
if (condition) { // Executes this block if // condition is true } else { // Executes this block if // condition is false }
Working of if-else statement
- Control falls into the if block.
- The flow jumps to Condition.
- Condition is tested.
- If Condition yields true, goto Step 4.
- If Condition yields false, goto Step 5.
- The if-block or the body inside the if is executed.
- The else block or the body inside the else is executed.
- Flow exits the if-else block.
Flowchart if-else:
Examples of if else statement in C++
Example 1:
Below program demonstrates the use of if else statements in C++.
// C++ program to illustrate if-else statement #include <iostream> using namespace std;
int main()
{ int i = 20;
// Check if i is 10
if (i == 10)
cout << "i is 10" ;
// Since is not 10
// Then execute the else statement
else
cout << "i is 20\n" ;
cout << "Outside if-else block" ;
return 0;
} |
i is 20 Outside if-else block
Explanation:
- Program starts.
- i is initialized to 20.
- if-condition is checked. i == 10, yields false.
- flow enters the else block.
- “i is 20” is printed
- “Outside if-else block” is printed.
Example 2:
Another program to illustrate the use of if else in C.
// C++ program to illustrate if-else statement #include <iostream> using namespace std;
int main()
{ int i = 25;
if (i > 15)
cout << "i is greater than 15" ;
else
cout << "i is smaller than 15" ;
return 0;
} |
i is greater than 15
Related Articles:
- Decision Making in C / C++
- C/C++ if statement with Examples
- C/C++ if else if ladder with Examples
- Switch Statement in C/C++
- Break Statement in C/C++
- Continue Statement in C/C++
- goto statement in C/C++
- return statement in C/C++ with Examples
- Program to Assign grades to a student using Nested If Else