#include <iostream>

int main()
{
    char str[100];
    std::cout << "Enter string: " << std::endl;
    std::cin.getline(str, 100);
    for(int i = 99; i > 0; i--) {
        if(str[i] == ' ') {
            std::cout << "last space index is: " << i << std::endl;
            break;
        }
    }
    return 0;
}