C++ If-else-if
Introduction:
If-else-if control statement is an if statement used with an optional else if control statement to check multiple conditions. In this control statement, when any one of the condition returns true, then none of the other else if or else will be executed. It allows a program to check many expressions consecutively and run the first block when the condition evaluates to true. If none of the conditions are met, an optional else block is run.
Syntax:
It has the following syntax:
if (condition1) {
// Code block executed if condition1 is true
}
else if (condition2) {
// Code block executed if condition2 is true
}
else if (condition3) {
// Code block executed if condition3 is true
}
else {
// Code block executed if none of the above conditions are true
}
Explanation:
- We start by examining the if block. The code for condition 1 runs and the subsequent ladder stages are omitted if it is true.
- If condition 1 is not true, the program moves on to else if (condition 2). If condition 2 is true, then its block is run and the others are ignored.
- Until a condition is judged to be actual, this process keeps going.
- The else block (if provided) runs if any of the conditions are untrue.
Algorithm:
Start Declare a variable to store input Accept input from the user Check conditions using If-Else-If: If condition1 is true → execute block 1 Else if condition2 is true → execute block 2 Else if condition3 is true → execute block 3 Else → execute the default block End
Pseudo code:
BEGIN
DECLARE variable
PRINT "Enter a value: "
READ variable
IF condition1 THEN
PRINT "Condition 1 is True"
ELSE IF condition2 THEN
PRINT "Condition 2 is True"
ELSE IF condition3 THEN
PRINT "Condition 3 is True"
ELSE
PRINT "None of the conditions are True"
ENDIF
END
Key Features:
Several key features of if-else-if statement in C++ are as follows:
- Order Matters: From top to bottom, conditions are examined in order. The others are disregarded as soon as a real condition is identified.
- Utilize Else for Default Execution: The else block makes sure that some code runs even in the event that none of the conditions are satisfied.
- Although if statements can be stacked within one another, the if-else-if form is typically more readable and effective.
- Avoid Redundant Conditions: In order to prevent needless checks, conditions should be logically ordered.
Example 1:
Let us take an example to illustrate the if-else-if statement in C++.
#include <iostream>
using namespace std;
int main()
{
int x = 50;
int y = 35;
if (x > y)
{
cout << "x is greater than y" << endl;
}
else if (y > x)
{
cout << "y is greater than x" << endl;
}
else
{
cout << "Both numbers are equal" << endl;
}
cout << "Value of x: " << x << ", Value of y: " << y;
return 0;
}
Output:
x is greater than y Value of x: 50, Value of y: 35
Example2:
In this example code, we determine the grade of the student basing upon the marks student scored:
#include <iostream>
using namespace std;
int main() {
int marks;
// Taking input from user
cout << "Enter your marks: ";
cin >> marks;
// If-else-if ladder to determine grade
if (marks >= 90) {
cout << "Grade: A+" << endl;
}
else if (marks >= 80) {
cout << "Grade: A" << endl;
}
else if (marks >= 70) {
cout << "Grade: B" << endl;
}
else if (marks >= 60) {
cout << "Grade: C" << endl;
}
else if (marks >= 50) {
cout << "Grade: D" << endl;
}
else {
cout << "Grade: F (Fail)" << endl;
}
return 0;
}
Output:
Enter your marks: 85 Grade: A Enter your marks: 45 Grade: F (Fail)
Example 3:
In this example, we determine the temperature whether it is hot or cold:
#include <iostream>
using namespace std;
int main() {
int temperature;
cout << "Enter the temperature: ";
cin >> temperature;
if (temperature >= 35) {
cout << "It's very hot!" << endl;
}
else if (temperature >= 25) {
cout << "The weather is warm." << endl;
}
else if (temperature >= 15) {
cout << "It's cool outside." << endl;
}
else {
cout << "It's cold outside!" << endl;
}
return 0;
}
Output:
Enter the temperature: 30 The weather is warm. Enter the temperature: 10 It's cold outside!
Conclusion:
In conclusion, the if-else-if statement in C++ is a fundamental decision-making structure that allows a computer to examine many conditions sequentially and, when a condition is met, run the corresponding block of code. When multiple possibilities need to be confirmed, such defining temperature levels, determining grades based on marks, or assessing user input, it is very useful. The structure makes the code more efficient and readable by restricting the amount of code blocks that run. Writing logical and structured programs that enable developers to properly build conditional processes requires an understanding of the if-else-if ladder. By using proper syntax and logical ordering, programmers can enhance the decision-making capabilities of their applications.