eng;ish to decimal code example

Example: english to decimal

#include<iostream>
#include<string>
#include<cmath>

int main()
{   

  
    std::cout<<"Please enter a string of small letters and spaces:\t";
    std::string str ;
    getline(std::cin, str) ;

    
    long int  result {0};
    long int  value {0};
    for(int i=0 ; i < str.length(); ++i)
    {

        switch(str[i]){
        
            case ' ':
                value = 0;
                break;
            case 'A':
            case 'a':
                value = 1;
                break;
            case 'B':
            case 'b':
                value = 2;
                break;
            case 'C':
            case 'c':
                value = 3;
                break;
            case 'D':
            case 'd':
                value = 4;
                break;
            case 'E':
            case 'e':
                value = 5;
                break;
            case 'F':
            case 'f':
                value = 6;
                break;
            case 'G':
            case 'g':
                value = 7;
                break;
            case 'H':
            case 'h':
                value = 8;
                break;
            case 'I':
            case 'i':
                value = 9;
                break;
            case 'J':
            case 'j':
                value = 10;
                break;
            case 'K':
            case 'k':
                value = 11;
                break;
            case 'L':
            case 'l':
                value = 12;
                break;
            case 'M':
            case 'm':
                value = 13;
                break;
            case 'N':
            case 'n':
                value = 14;
                break;
            case 'O':
            case 'o':
                value = 15;
            case 'P':
            case 'p':
                value = 16;
                break;
            case 'Q':
            case 'q':
                value = 17;
                break;
            case 'R':
            case 'r':
                value = 18;
                break;
            case 'S':
            case 's':
                value = 19;
                break;
            case 'T':
            case 't':
                value = 20;
                break;
            case 'U':
            case 'u':
                value = 21;
                break;
            case 'V':
            case 'v':
                value = 22;
                break;
            case 'W':
            case 'w':
                value = 23;
                break;
            case 'X':
            case 'x':
                value = 24;
                break;
            case 'Y':
            case 'y':
                value = 25;
                break;
            case 'Z':
            case 'z':
                value = 26;
                break;
            default:
                std::cout<<" The input string does not represent a number in base 27 "<<std::endl;
        } 
        int power = (str.length()-1-i);
        result += value*(pow(27,power));
    }
    if(str.length()>= 32)
    {           
        std::cout<<"\nThe input string represents a number that is greater than 2ˆ32"<<std::endl;
        
    }else{
        std::cout<<"\n"<<result<<std::endl;
    }
    

    return 0 ;
}