Sequence of If-Else Conditions

Sometimes we need to do a sequence of conditions before we decide what actions our program will execute. In such cases, we can apply the construction if-else if ... -else in series. For this purpose, we use the following “chained if-else” format:

if (condition)
{
    // condition body;
}
else if (second condition)
{
    // condition body;
}
else if (third condition)
{
    // condition body;
}
…
else
{
    // else construction body;
}

Video: Series of If-Else Checks

Watch the video lesson about the if-else checks: https://youtu.be/PUvf7gtKSz4.

Example: Digits in English

Print the digits in the range of 1 to 9 (digits are read from the console) in English. We can read the digit and then, through a sequence of conditions we print the relevant English word:

int num = int.Parse(Console.ReadLine());

if (num == 1)
{
    Console.WriteLine("one");
}
else if (num == 2)
{
    Console.WriteLine("two");
}
else if (…) 
{
    …
} 
else if (num == 9)
{
    Console.WriteLine("nine");
} 
else 
{
    Console.WriteLine("number too big");
}

The program logic from the above example sequentially compares the input number from the console with the digits from 1 to 9, when each following comparison is being performed only in case the previous comparison is not true. Eventually, if none of the if statements are true, the last else clause is performed.

Testing in the Judge System

Test your solution here: https://judge.softuni.org/Contests/Practice/Index/506#4.