C++ functions and random number - c++

Question

When I write this code:
#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;
int random = std::rand() % 9 + 1;
int main()
{
std::srand(std::time(0));
if(random==1 || random ==2 || random == 3){
cout << "Wolf" << endl;
} else if(random==4 || random ==5 || random == 6){
cout << "Bear" << endl;
} else if(random==7 || random ==8 || random == 9){
cout << "Pig" << endl;
}
}
Every time I run it I get something else printed(Wolf, Pig or Bear), like I wanted.
But when I add this function in my code like this:
#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std;
int random = std::rand() % 9 + 1;
void func(){
if(random==1 || random ==2 || random == 3){
cout << "Wolff" << endl;
} else if(random==4 || random ==5 || random == 6){
cout << "Bearr" << endl;
} else if(random==7 || random ==8 || random == 9){
cout << "Pigg" << endl;
}
}
int main()
{
std::srand(std::time(0));
if(random==1 || random ==2 || random == 3){
cout << "Wolf" << endl;
func();
} else if(random==4 || random ==5 || random == 6){
cout << "Bear" << endl;
func();
} else if(random==7 || random ==8 || random == 9){
cout << "Pig" << endl;
func();
}
}
I want every time I run it to get printed something else like Bear Bearr, Wolf Wolff or Pig Pigg.But with this function whenever I run it I get the same result.What is the problem?
Please help me, I'm new in C++.

Answer 1

The global initializers are executed before main is called. So you never reseed your PRNG, and thus always draw the same "random" numbers.
That said, I don't believe that either of your code pieces produce different output with each run, since they have the same initialization order problem.

Answer 2

EDIT: Changing to match your stated goal of "bear", "bearr", "pig", "pigg".
int random = std::rand() % 9 + 1;
declares a global variable called "random" which is assigned a value during startup, before main(). The value will be the (default return value of rand() modulo'd by 9) plus one. It does not automatically change.
What you appear to be looking for is
int random()
{
return (std::rand() % 9) + 1;
}
which defines a function that calls rand, modulos the value by 9 and then returns one. EDIT: To see the same value inside the "func()" function, pass it by value or reference as a function parameter:
#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using std::cout;
using std::endl;
int random() {
return (std::rand() % 9) + 1;
}
void func(int randNo){
switch (randNo) {
case 1: case 2: case 3:
cout << "Wolff" << endl;
break;
case 4: case 5: case 6:
cout << "Bearr" << endl;
break;
case 7: case 8: case 9:
cout << "Pigg" << endl;
break;
}
}
int main()
{
std::srand(std::time(0));
int randNo = random();
switch (randNo) {
case 1: case 2: case 3:
cout << "Wolf" << endl;
func(randNo);
break;
case 4: case 5: case 6:
cout << "Bear" << endl;
func(randNo);
break;
case 7: case 8: case 9:
cout << "Pig" << endl;
func(randNo);
break;
}
cout << "And now for something completely different." << endl;
for (size_t i = 0; i < 10; ++i) {
cout << i << ": ";
func(random());
}
}