Nested if in C++

 If is a type of condition checking in which a condition turns out to be true a block of statements is executed.

Syntax:

// if base_condition is true
// every inside the { } block will be executed
if (base_condition)
{
    statement 1...............
    statement 2 ..............
}

Example

• C++

// C++ Program demonstrate // use if-else condition #include <iostream> using namespace std;   int main() {     int a = 7, b = 6;     if (a > b) {         cout << "True" << endl;     } }

Output

True

What is Nested If?

When a number of if blocks are present one after another with the same scope (the same scope means under one { } block), then that condition is termed as a Nested if condition. If the first condition is True, we go into the next if condition and the subsequent condition is checked until we get a false condition, and the checking stops.

Syntax:

 if base_condition is true control goes to base_condition1
if ( base_condition) 
{
    // if base_condition is true control goes to base_condition2
    if(base_condition1) 
    {
        if(base_condition2) 
            ..........................
        ..........................
    }
}

Example 1:

• C++

// C++ Program to // Nested-if conditions #include <iostream> using namespace std;   int main() {       int a = 20, b = 10, c = 2;       // if this condition satisfies then     // control goes to next if condition     if (a > b) {         // if this condition also turns out to be         // true then the statements under         // this block will get executed         if (a > c) {             cout << " a is the largest " << endl;         }     }     return 0; }

Output

 a is the largest 

Example 2:

• C++

// C++ Program to // Nested-if conditions #include <iostream> using namespace std;   int main() {       int a = 20, b = 10, c = 2;       if (a == 20) {         if (b == 10) {             if (c == 2) {                 cout << "Sandeep Sir is Great!!" << endl;             }         }     }     return 0; }

Output

Sandeep Sir is Great!!

Example 3:

• C++

// C++ Program to // Nested-if conditions #include <iostream> using namespace std;   int main() {       int a = 20, b = 10, c = 1;     // this condition is true     if (a == 20) {         // this condition is also true         if (b == 10) {             // but this condition is false hence             // we get out of the nested block             if (c == 2) {                 cout << "Sandeep Sir is Great!!" << endl;             }         }     }     cout << "gfg\n";       return 0; }

Output

gfg

Example 4:

• C++

// C++ Program to demonstrate // Nested-if condition #include <iostream> using namespace std;   int main() {       int a = 220, b = 10, c = 1;     // this condition is itself false we don't     // get inside the nesting if block     if (a == 20) {         if (b == 10) {             if (c == 2) {                 cout << "Sandeep Sir is Great!!" << endl;             }         }     }     cout << " No nested if condition is executed \n ";     return 0; }

Output

 No nested if condition is executed 
 

Time complexity: O(1).

Auxiliary space: O(1).

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