If Statements

Let’s have the program perform different tasks under different conditions. A person may think, "Oh gee, here comes the hard part." Digital Reference says, "DON’T SWEAT IT!" By using the if statement, you can have a fine and dandy program that runs errands under certain "requirements."

Here is how to set up your if statement:

if(type here under what condition this program should perform the task)
     type your assignment statement here;

The "requirement" of the if statement is also known as a Boolean expression. It can be true or false. If the Boolean expression is true, meaning if such a condition exists, then the program will run the task it is assigned. However, if the expression is false, the program will skip the task.

Relational operators can be used in a Boolean expression. < means less than. > means greater than. <= means less than or equal to. >= greater than or equal to. != means does not equal to. = = means equal to.

Let’s say, if the variable x equals 1, we want the program the program to display "False." We would write the following if statement:

if (x == 1)
   cout << "False";

if-else statements

We can also have the program run a task under a certain condition. If the condition is not met, the program can run another task otherwise. This is done so by writing if-else statements. For example, if the variable x equals 1, the program will display "False." Otherwise, if the variable x represents another value, display "True." We would write the following if-else statements:

if (x == 1)
    cout << "False";
else
    cout << "True";

Sometimes you want the program to perform more than one task under a certain condition. It is possible! All you have to do is use a brace to enclose the statements. These statements are called compound statements. Here is an example:

If the variable x equals 1, display, "Hi" on one line, and "How are you?" on the next line. If the variable x represents another value other than 1, display "See you!" on one line, and "Please come back another time" on the next line." This is how you write the if-else statements consisting of the compound statements:

if(x == 1){
     cout << "Hi" << endl;
     cout << "How are you?";
}else{
     cout << "See you!" << endl;
     cout << "Please come back another time" << endl;
}

Nested if statements

Let’s say you want the program to perform a certain task under a certain condition, and this certain condition will run only if another condition is met. Then, you will need to use nested if statements.

Here is an example:

If the variable x equals 100, we want the program to display "Perfect Score." Otherwise, if x does not equal 100, but if x is greater than or equal to 60, display "Pass." If x is not greater than or equal to 60, display, "Fail."

if (x = = 100)
    cout << "Perfect Score";
else
    if(x >=60)
           cout << "Pass";
   else
        cout << "Fail";

Switch Statements

When you use if statements, the condition is in bool. Switch statements are very similar to the if statements. However, they are in a different format.

This is how switch statements look like:

switch (variable type)
{
      case value_here:     assignment statement here;
                                 break;
      case value1_here:    assignment statement here;
                                 break;
      ....
      default:                       assignment statement here;
}

The case is equivalent to the if(condition). The default is equivalent to the else in an if-else statement. The break statement ends a section of code. It is very important to use the break statement after every case in the switch statement, because the assignment statement for that case can be shared with another case when there is no break statement.

(The break statement will be explained later in the Loops section.)

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