SparkContext is the first object that a Spark program must create to access the cluster. In spark-shell, it is directly accessible via spark.sparkContext. Here's how you can programmatically create SparkContext in your Scala code:
import org.apache.spark.SparkContext
import org.apache.spark.SparkConf
val conf = new SparkConf().setAppName("my app").setMaster("master url")
new SparkContext(conf)