How can I input multiple variables on the same line C++

Question

So I am trying to input multiple variables on the same line and have it call a function and parse some of the variables to a function it will call. For example the user will enter something like

COMMAND <integer>

I have tried using scanf however when it does work it doesn't seem to recognize the variable I passed. I am certain I am just making a silly mistake but can someone please help me? I wrote a simple program to try to test passing variables like this which I have included below.

#include <iostream>
#include<stdio.h>
#include<string>

using namespace std;

string derp(int test) {
    cout << "and here " + test << endl;
    return "derp " + test;
}


void main() {
    char command[20];
    int *bla(0);
    scanf("%s %u", &command[0], &bla );
    if (strcmp(command, "derp") == 0) {
        cout << "works here" << endl;
        cout << derp(*bla);
    }
}

Answer 1

Change: int *bla(0); from being a pointer to an actual variable: int bla(0);

Same goes for output: cout << derp(*bla); to cout << derp(bla); (no longer need dereferencing on bla).

Also, you can't output a sum of a C-string + an int, it's not concatenation. Use chained output:

cout << "and here " + test << endl; should be cout << "and here " << test << endl;

and

return "derp " + test; should be fixed for the same reason.

Fixed version:

#include <iostream>
#include<stdio.h>
#include<string>

using namespace std;

string derp(int test) {
    cout << "and here " << test << endl;
    return std::string("derp ") + to_string(test);
}


void main() {
    char command[20];
    int bla(0);
    scanf("%s %u", &command[0], &bla);
    if (strcmp(command, "derp") == 0) {
        cout << "works here" << endl;
        cout << derp(bla);
    }
}