Choosing one of two strings to output? - c++

Question

I was wondering how I could have a program output one of two strings at random.
Hard to explain but this is my example:
#include <iostream>
#include <string>
using namespace std;
int main()
{
string age;
cout << "How old are you?" << endl;
cin >> age;
if (age < 0)
{
cout << "Invalid age" << endl;
}
if (0 >= age && age <<= 3)
{
cout << "Oh you're just a baby" << endl;
// OR (random)
cout << "Time to take a nap!" << endl;
}
return 0;
}
I want to program to output either, "Oh, you're just a baby" or "Time to take a nap!" at random whenever the user inputs a number between 0 and 3. Can anybody explain this?

Answer 1

try :
#include <cstdlib>
...
...
...
/* initialize random seed: */
srand(time(NULL));
/* generate secret number: */
int ss = rand() % 2;
if (ss) {
cout << "Oh you're just a baby" << endl;
} else {
cout << "Time to take a nap!" << endl;
}

Answer 2

You can also try this:
take input from user and compare it to random generated value and print output according to it:
#include <iostream>
using namespace std;
int main()
{
int age;
srand(time(NULL));
int a = rand()%3;
cout<<a<<endl; // print the random generated number (between 0 and 3 )
cout << "How old are you?" << endl;
cin >> age;
if (age < 0)
{
cout << "Invalid age" << endl;
}
if(age == a){
cout << "Oh you're just a baby" << endl;
}else{
cout << "Time to take a nap!" << endl;
}
return 0;
}

Answer 3

This uses the STL and only does the random selection from a table, without any user input:
#include <array>
#include <chrono>
#include <cstddef>
#include <iostream>
#include <random>
using std::cout;
using std::endl;
int main(void) {
// The size of the table:
constexpr size_t n = 2;
// A table of insults:
constexpr std::array<const char*, n> insults = {
"Oh, you're just a baby!",
"Time to take a nap."
};
// Boilerplate to initialize a RNG:
const std::default_random_engine::result_type seed = std::chrono::system_clock::now().time_since_epoch().count();
std::default_random_engine generator (seed);
// Generate a random index into the string table:
std::uniform_int_distribution<size_t> distribution(0, n-1);
// A random number from distribution:
const size_t x = distribution(generator);
// Our random string:
const char* const s = insults[x];
cout << s << endl;
return EXIT_SUCCESS;
}