C ++一次打印一个字母。 如何？

Question

Let's say i have a string, that contains a message. If i want to print it on the screen, i just can do cout<<string, or cout<<"Hello!" . But the message gets printed all at once.

So what i am looking for is a function that takes a message and a number as input variables, and prints the message one letter at the time, using the number as delayer.

Like this:

void slow_print("Hello!", 5); This means print each letter with 5 seconds of delay between them.

Unfortunately, i have no idea how to do that (except for the delay, wich you can do with the Sleep() function), and so i came up with this ugly looking solution:

string A = "A", B = "B", C = "C", D = "D", E = "E" .... //etcetera...

Then i would declare a vector, wich contains those letters. So then i could do a for loop, for instance, that prints one vector cell at the time.

vect[dimension] = { H,e,l,l,o,_,h,o,w,_,a,r,e,_,y,o,u }

        for (int i = 0; i<dimension; i++)
    { 
      cout<<vect[dimension];
      Sleep(delay_time);
    }

This is the only solution i have found. It works but, it is very uncomfortable to use.

Does anyone have a better idea? I hope the community can help me :)

Thanks for your time.

Answer 1

You can actually index the individual characters of a std::string . Your function could look like this:

void slow_print(const std::string& str, int delay_time) {
    for (size_t i = 0; i != str.size(); ++i) { 
        std::cout << str[i];
        Sleep(delay_time);
    }
}

Answer 2

You can use something like that:

unsigned long k;
std::string str="Hello"
for (k=0;k<str.size();++k) {
    std::cout << str[k]; Sleep(5);
}

You are able to index a string. If str is equal to "Hello" , str[0] , for example, will be equal to 'H' .

Answer 3

If you use c++11 or later...

std::string str("hello.");
std::for_each(str.begin(), str.end(), [](char c){
    std::cout << c;
    Sleep(1000);
});

std::for_each comes from <algorithm>.