How to run a simple c program in solo learn

Question

i am unable to run a simple program like in pc

Answer 1

#include<cstdio>
using namespace std;
int main()
{
int num;
printf("\n Enter a number : ");
scanf("%d", &num);
if(num==1)
{
printf(" Hello World");
}
return 0;
}

Answer 2

c or c#?