Easy tutorial for C / C++ Control statement 1 (if, if else statements)

Easy tutorial for C / C++ Control statement 1 (if, if else statements)

- Normally in a computer program, the statements are executed in the order in which they were written (down from the top of the code).

- However, depending on the situation, you may want to run only when the conditions are right or sometimes you want to do it with certain rules.

- For this purpose, control statements (such as an if statement, a for statement, a while statement, etc.) are provided.

- The advantage of using control statements is that they can be efficient and simple to code.

- First, let's summarize the control statements that are executed under certain conditions.

if statement :

- The 'if' statement is a statement that says to execute a specific statement if the condition is satisfied. The structure of 'if' statement is as follows:

if ('condition') {'execute statement'}

- If this 'condition' is satisfied, it executes the execution statement and does not execute if the condition is not satisfied.

- The 'condition' statement usually uses a conditional expression that evaluates the result as true or false. Depending on the situation, an expression that gives a result of 1 or 0 is used. In this case, 1 is true and 0 is false.

Example Code

#include <iostream>

using namespace std;

int main() {

     int a ;

          a = 3 ;

     if(a > 1){

             cout<<" a > 1 is true !!! "<<endl ;

          }

          return 0;

}

results:

a > 1 is true !!!

- Declares an integer variable a and assigns 3 to a. In the if statement, the conditional statement has a condition of a > 1.

- 3 is stored in a and thus a is larger than 3, so the result is true. The following statement is executed: "a> 1 is true !!!"

if else statement :

- The structure of 'if else' statement is as follows:

if ('condition') {'execute statement 1'}

else{'execute statement 2'}

- If the condition is satisfied, 'execution statement 1' is executed. If condition is not satisfied, 'execution statement 2' is executed.

Example Code

#include <iostream>

using namespace std;

int main() {

     int a, b;

          a = 3 ;

          b = 1 ;

     if( a > 2 ){

           cout<<" a > 2 is true !!! "<<endl ;

          } else {

           cout<<" a > 2 is false !!! "<<endl ;

          }

     if( b > 2 ){

           cout<<" b > 2 is true !!! "<<endl ;

          } else {

           cout<<" b > 2 is false !!! "<<endl ;

          }

           return 0;

}

results:

a > 2 is true !!!

b > 2 is false !!!

- 'a' has a value of 3. In the first 'if' statement, 'a' is greater than 2, so the "a> 2 is true !!!" is printed.

- 1 was assigned to 'b'. Because the condition of the second 'if' statement is not satisfied, the "b> 2 is false !!!" is printed.