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DecConditional Statements in C++: if , if..else, if-else-if and nested if
Conditional Statements in C++: An Overview
The flow of a program is managed using conditional statements in C++. If a condition is true inside the if
statement, the body of the statement executes. If false, else
is used to specify an alternate course of action. You can check several criteria sequentially using the else-if
statement and learn C++ from scratch. For multi-way branching based on the result of an expression, use the switch
statement. You can also check our C++ Certification Course for in-depth knowledge of C++.
Conditional Statements in C++ programming?
In C++, conditional statements are control structures that let code make decisions. These statements are also known as decision-making statements. They are of the type if
statement, if-else
, if else-if ladder
, switch
, etc. These statements determine the flow of the program execution.
Types of Conditional Statements in C++
In this article, we'll discuss the first kind of conditional statement i.e. if...else
statements in C++. We'll discuss the switch
statement in the next tutorial switch statement in C++.
if … else statements
if-else
is the first kind of control statement in C++. In this, the operations are performed according to some specified condition. The statements inside the body of the if
block get executed if and only if the given condition is true.
Read More - Advanced C++ Interview Interview Questions and Answers
Variants of if-else statements in C++
We have four variants of if-else
statements in C++. They are:
if
statement in C++if-else
statement in C++if else-if ladder
in C++nested if
statement in C++
- if statement in C++
if
statements in C++ are one of the most simple statements for deciding in a program. When you want to print any code only upon the satisfaction of a given condition, go with the simple if
statement.
Syntax
if(testcondition)
{
// Statements to execute if
// condition is true
}
- In the
if
statement, the test condition is in()
. - If the
testcondition
becomestrue
, the body of theif
block executes else no statement of theif
block gets printed.
Example
// C++ program to understand if statement
#include <iostream>
using namespace std;
int main()
{
int i = 11;
if (i > 15)
{
cout << "11 is greater than 15";
}
cout << "I am Not in if";
return 0;
}
This C++ code in C++ Compiler initializes the integer i
to 11 and then checks to see if it is greater than 15 using an if
statement. It outputs "I am Not in if" to the console because 11 is not greater than 15.
Output
I am Not in if
- if-else statement in C++
It is an extension of the if
statement. Here, there is an if
block and an else
block. When one wants to print output for both cases - true
and false
, use the if-else
statement.
Syntax
if (testcondition)
{
// Executes this block if
// condition is true
}
else
{
// Executes this block if
// condition is false
}
Example
// C++ program to understand the if-else statement
#include <iostream>
using namespace std;
int main()
{
int A = 16;
if (A < 15)
cout << "A is smaller than 15";
else
cout << "A is greater than 15";
return 0;
}
This C++ program initializes the integer variable A
to 16 and then checks to see if it is less than 15 using the if-else
statement. It outputs "A is greater than 15" to the console because it isn't.
Output
A is greater than 15
- nested if statement in C++
We can include an if-else
block in the body of another if-else
block. This becomes a nested if-else
statement.Syntax
if(test condition1)
{ //if condition1 becomes true
if(test condition1.1)
{
//code executes if both condition1 and condition 1.1 becomes true
}
else
{
//code executes if condition1 is true but condition 1.1 is false
}
}
else
{
//code executes if condition1 becomes false
}
Example
// C++ program to understand nested-if statement
#include <iostream>
using namespace std;
int main() {
int a = 10;
int b = 5;
if (a > b) {
// Control goes to the nested if
if (a % 2 == 0) {
cout << a << " is even";
}
else {
cout << a << " is odd";
}
}
else {
cout << a << " is not greater than " << b;
}
return 0;
}
- In the above code in C++ Editor, the first
if
statement checks whethera>b
. - If
a
is greater thanb
, thenested if
statement is checked. - If the
nested if
condition isfalse
, theelse
statement in thenested if
block gets executed. - If the first
if
statement evaluates tofalse
, thenested if
block gets skipped and theelse
block executes.
Output
10 is even
- if else-if ladder in C++
It is an extension of the if-else
statement. If we want to check multiple conditions if the first if
condition becomes false
, use the if else-if ladder
. If all the if
conditions become false
the else
block gets executed.
Syntax
if (testcondition1)
statement;
else if (testcondition2)
statement;
.
.
else
statement;
Example
// C++ program to understand if-else-if ladder
#include <iostream>
using namespace std;
int main()
{
int A = 20;
if (A == 10)
cout << "A is 10";
else if (A == 15)
cout << "A is 15";
else if (A == 20)
cout << "A is 20";
else
cout << "A is not present";
return 0;
}
Theif else-if
ladder is shown in this section of C++ code. It sequentially compares the value of A
to several conditions. It outputs "A is 20"as the condition matched and comes out of the ladder.
Output
A is 20
Summary
This article gives a vast idea about if-else
conditional statement in C++ language, including its various types with syntax and examples. If you've understood everything we went over in this blog post, congratulations! Now you can check out for a C++ certificationto get some more insights and practice on such an important programming concept.
FAQs
- Incorrect logic: Double-check your conditions for errors and ensure they accurately represent your desired behavior.
- Missing braces: Braces are crucial for defining the code block associated with each condition.
- Infinite loops: Be cautious with conditions that might never become false, leading to an endless loop.
- Dangling else: Ensure an else statement belongs to the correct if condition.