To run: Compile and "./collatz <integer>". Collatz Conjecture in C++. Left column is the number of steps to get to 1.

collatz.cpp

// Warning: maximum value for a variable of type int: 2,147,483,647
#include <stdio.h>
int main(int argc, char *argv[]){
	if(argc == 2){
		int x = atoi(argv[1]); int n = 0; printf("%i %i\n",n,x);
    if(x < 1){
      exit(1);
    }
    else{
      while(x != 1){
        if(x%2 == 0){
          x = x/2; n++; printf("%i %i\n",n,x);
        }
        else{
          x = (3*x)+1; n++; printf("%i %i\n",n,x);
        }
      }
    }
	}
  else{
    exit(1);
  }
}