Nested switch case

Difficulty Level : Medium
Last Updated : 16 Jan, 2020

Switch-case statements:

These are a substitute for long if statements that compare a variable to several integral values

The switch statement is a multiway branch statement. It provides an easy way to dispatch execution to different parts of code based on the value of the expression.
Switch is a control statement that allows a value to change control of execution.

Points to remember while using Switch Case

The expression used in a switch statement must have an integral or character type, or be of a class type in which the class has a single conversion function to an integral or character type.
There can be any number of case statements within a switch. Each case is followed by the value to be compared to and after that a colon.
When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached.
When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement.
Not every case needs to contain a break. If no break appears, the flow of control will fall through to subsequent cases until a break is reached i.e. all the case statements will get executed as soon as compiler finds a comparison to be true.
A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true. No break is needed in the default case.

Syntax:

switch (n)
{
    case 1: // code to be executed if n = 1;
  break;
    case 2: // code to be executed if n = 2;
  break;
    default: // code to be executed if 
      // n doesn't match any cases
}

Nested-Switch Statement:

Nested-Switch statements refers to Switch statements inside of another Switch Statements.

Syntax:

switch(n)
{
  // code to be executed if n = 1;
  case 1: 
    
  // Nested switch
  switch(num) 
  {
    // code to be executed if num = 10
    case 10: 
      statement 1;
      break;
      
    // code to be executed if num = 20
    case 20: 
      statement 2;
      break;
      
    // code to be executed if num = 30
    case 30: 
      statement 3;
      break;
      
      // code to be executed if num 
      // doesn't match any cases
      default: 
  }
  
  
  break;
    
  // code to be executed if n = 2;
  case 2:
    statement 2;
    break;
  
  // code to be executed if n = 3;
  case 3: 
    statement 3;
    break;
  
   // code to be executed if n doesn't match any cases
   default: 
}

Example:

// Following is a simple program to demonstrate 
// syntax of Nested Switch Statements. 
#include <stdio.h> 
  
int main() 
{ 
    int x = 1, y = 2; 
  
    // Outer Switch 
    switch (x) { 
  
    // If x == 1 
    case 1: 
  
        // Nested Switch 
  
        switch (y) { 
  
        // If y == 2 
        case 2: 
            printf( "Choice is 2"); 
            break; 
  
        // If y == 3 
        case 3: 
            printf( "Choice is 3"); 
            break; 
        } 
        break; 
  
    // If x == 4 
    case 4: 
        printf( "Choice is 4"); 
        break; 
  
    // If x == 5 
    case 5: 
        printf( "Choice is 5"); 
        break; 
  
    default: 
        printf( "Choice is other than 1, 2 3, 4, or 5"); 
        break; 
    } 
    return 0; 
} 

Output:

Choice is 2

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