PHP Tutorial Part 14 : PHP If Else

PHP If Else PHP if-else statement is used to test condition. There are various ways to use if statement in PHP. if if-else if-else-if nested if PHP If Statement PHP if statement allows conditional execution of code. It is executed if the condition is true. If the statement is used to executes the block of code that exists inside the if statement only if the specified condition is true. Syntax if(condition){   //code to be executed   }   Flowchart if(condition){ //code to be executed } Example <?php   $num=12;   if($num<100){   echo "$num is less than 100";   }   ?>   <?php $num=12; if($num<100){ echo "$num is less than 100"; } ?> Output: 12 is less than 100 PHP If-else Statement PHP if-else statement is executed whether the condition is true or false. If-else statement is slightly different from the if statement. It executes one block of code if the specified condition is true and another block of code if the condition is false. Syntax if(condition){   //code to be executed if true   }else{   //code to be executed if false   }   if(condition){ //code to be executed if true }else{ //code to be executed if false } Flowchart Example <?php   $num=12;   if($num%2==0){   echo "$num is even number";   }else{   echo "$num is odd number";   }   ?>   <?php $num=12; if($num%2==0){ echo "$num is even number"; }else{ echo "$num is odd number"; } ?> Output: 12 is even number PHP If-else-if Statement The PHP if-else-if is a special statement used to combine multiple if?.else statements. So, we can check multiple conditions using this statement. Syntax if (condition1){     //code to be executed if condition1 is true     } elseif (condition2){       //code to be executed if condition2 is true     } elseif (condition3){       //code to be executed if condition3 is true     ....   }  else{     //code to be executed if all given conditions are false     }     if (condition1){ //code to be executed if condition1 is true } elseif (condition2){ //code to be executed if condition2 is true } elseif (condition3){ //code to be executed if condition3 is true .... } else{ //code to be executed if all given conditions are false } Flowchart Example <?php       $marks=69;           if ($marks<33){             echo "fail";         }         else if ($marks>=34 && $marks<50) {             echo "D grade";         }         else if ($marks>=50 && $marks<65) {            echo "C grade";        }         else if ($marks>=65 && $marks<80) {             echo "B grade";        }         else if ($marks>=80 && $marks<90) {             echo "A grade";         }       else if ($marks>=90 && $marks<100) {             echo "A+ grade";        }      else {             echo "Invalid input";         }     ?>   <?php $marks=69; if ($marks<33){ echo "fail"; } else if ($marks>=34 && $marks<50) { echo "D grade"; } else if ($marks>=50 && $marks<65) { echo "C grade"; } else if ($marks>=65 && $marks<80) { echo "B grade"; } else if ($marks>=80 && $marks<90) { echo "A grade"; } else if ($marks>=90 && $marks<100) { echo "A+ grade"; } else { echo "Invalid input"; } ?> Output: B Grade PHP nested if Statement The nested if statement contains the if block inside another if block. The inner if statement executes only when the specified condition in outer if the statement is true. Syntax if (condition) {     //code to be executed if condition is true    if (condition) {     //code to be executed if condition is true     }     }    if (condition) { //code to be executed if condition is true if (condition) { //code to be executed if condition is true } } Flowchart Example <?php                  $age = 23;       $nationality = "Indian";       //applying conditions on nationality and age       if ($nationality == "Indian")       {           if ($age >= 18) {               echo "Eligible to give vote";           }           else {                 echo "Not eligible to give vote";           }       }   ?>   <?php $age = 23; $nationality = "Indian"; //applying conditions on nationality and age if ($nationality == "Indian") { if ($age >= 18) { echo "Eligible to give vote"; } else { echo "Not eligible to give vote"; } } ?> Output: Eligible to give vote PHP Switch Example <?php                 $a = 34; $b = 56; $c = 45;       if ($a < $b) {           if ($a < $c) {               echo "$a is smaller than $b and $c";           }       }   ?>   Output: 34 is smaller than 56 and 45