C # if ... else statement
After aif statement with an optional else statement,else statement executes the Boolean expression is false.
grammar
The syntax in C #if ... else statement:
if (boolean_expression) { / * If the Boolean expression is true will execute statement * / } else { / * If the Boolean expression is false statements that will be executed * / }
If the Boolean expression istrue, then the code ifthe execution block. If the Boolean expression isfalse, then the code within the elseblock executed.
flow chart
Examples
using System; namespace DecisionMaking { class Program { static void Main (string [] args) { / * Local variable definitions * / int a = 100; / * * Check boolean condition / if (a <20) { / * If the condition is true, the output following statement * / Console.WriteLine ( "a less than 20"); } else { / * If the condition is false, the output of the following statements * / Console.WriteLine ( "a greater than 20"); } Console.WriteLine ( "a value is {0}", a); Console.ReadLine (); } } }
When the above code is compiled and executed, it produces the following results:
a greater than 20 a value of 100
if ... else if ... else statement
After aif statement with an optional else if ... elsestatement, which can be used to test a variety of conditions.
When using if ... else if ... else statement, the following points should be noted:
- If a post can be followed by zero or one else, it must be after any one else if.
- If the latter can be followed by zero or more else if, they must precede else.
- Once a successful match else if, else if or else the other will not be tested.
grammar
In C #if ... else if ... else statement syntax:
if (boolean_expression 1) { / * When a Boolean expression is true execution * / } else if (boolean_expression 2) { / * When the Boolean expression 2 is true execution * / } else if (boolean_expression 3) { / * 3 When the Boolean expression is true execution * / } else { / * When the above conditions are not true, are executed * / }
Examples
using System; namespace DecisionMaking { class Program { static void Main (string [] args) { / * Local variable definitions * / int a = 100; / * * Check boolean condition / if (a == 10) { / * If the if condition is true, then the output of the following statements * / Console.WriteLine ( "a value of 10"); } else if (a == 20) { / * If the else if condition is true, then the output of the following statements * / Console.WriteLine ( "a value of 20"); } else if (a == 30) { / * If the else if condition is true, then the output of the following statements * / Console.WriteLine ( "a value of 30"); } else { / * If the above conditions are not true, then output the following statement * / Console.WriteLine ( "no matching value"); } Console.WriteLine ( "a precise value is {0}", a); Console.ReadLine (); } } }
When the above code is compiled and executed, it produces the following results:
Exact value does not match the value of a is 100