Why is my code stopping prematurely? what have i done wrong? - c++

Question

I'm just starting so I'm trying to write a program which determine if a number is positive or negative.
#include <iostream>;
int step_function(int x) {
int result = 0;
if (x > 0)
result = 1;
else if (x < 0)
result = -1;
else
result = 0;
return result;
}
using namespace std;
int main() {
int num;
cout<< "please enter number : ";
cin >> num;
int a = step_function(num);
if (a == 1)
printf("%d is positive", num);
else if (a == -1)
printf("%d is negative", num);
else
printf(" it is zero");
return 0;
}

Answer 1

There is a few things you should do:
First things first you should get yourself a Good Book for C++.
Second thing is read why using namespace std; is a bad idea.
Lastly here is your code fixed. You needed to remove the semicolon as well as removing the printf(). I also removed the using namespace std; which made it more readable.
#include <iostream>
int step_function(int); //Function prototype
int main() {
int num;
std::cout << "please enter number : ";
std::cin >> num;
int a = step_function(num);
if (a == 1)
std::cout << num << " is postive";
else if (a == -1)
std::cout << num << " is negative";
else std::cout <<" it is zero";
return 0;
}
int step_function(int x)
{
int result = 0;
if (x > 0) result = 1;
else if (x < 0) result = -1;
else result = 0;
return result;
}

Answer 2

Don't use semicolon after #include <iostream>.
I think for C++ cout is more standard whereas printf is from C.
You can also include printing of the text in the step_function. Also, it's better to use braces {} after if and else statements for clarity especially if the code becomes complex.
#include <iostream>
using namespace std;
void step_function(int x) {
if (x > 0) {
cout << x << " is positive" << endl;
}
else if (x < 0) {
cout << x << " is negative" << endl;
}
else {
cout << "it is zero" << endl;
}
}
int main() {
int num;
cout<< "please enter number : ";
cin >> num;
step_function(num);
return 0;
}