why we use switch statement in c++ code example

Example 1: c++ switch case statement

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
}

Example 2: how to make a switch case statement in c++

#include <iostream>
using namespace std;
int main(){
   int num = 5;
   switch(num + 2) {
      case 1: 
        cout << "Case1: Value is: " << num << endl;
      case 2: 
        cout << "Case2: Value is: " << num << endl;
      case 3: 
        cout << "Case3: Value is: " << num << endl;
      default: 
        cout << "Default: Value is: " << num << endl;
   }
   return 0;
}