In C++, there is a control flow statement known as the switch statement that offers an effective method of handling numerous situations of a single expression. It allows you to compare the value of an expression to a list of possible constant values and execute code blocks based on the match.

Here is the fundamental syntax of the switch statement in C++:

switch (expression) {
    case value1:
        // If expression equals value1, run this code.
        break;
    case value2:
        //If expression equals value2, run this code.
        break;
    // ... more cases ...
    default:
        //If none of the cases match, run the following code.
}

example:-

#include <iostream>

int main() {
    char g = 'B';

    switch (g) {
        case 'A':
            std::cout << "case A" << std::endl;
            break;
        case 'B':
            std::cout << "case B" << std::endl;
            break;
        case 'C':
            std::cout << "case C" << std::endl;
            break;
        case 'D':
            std::cout << "case D." << std::endl;
            break;
        default:
            std::cout << "case default." << std::endl;
    }

    return 0;
}