#include "NativeSumDemo.h"

JNIEXPORT jdouble JNICALL Java_NativeSumDemo_sum
  (JNIEnv *env, jclass cls, jdoubleArray arr)
{
    jdouble sum = 0;
    jsize len = env->GetArrayLength( arr );
    
      // Get the elements; don't care to know if copied or not
    jdouble *a = env->GetDoubleArrayElements( arr, NULL );
    
    for( jint i = 0; i < len; i++ )
        sum += a[ i ];
        
      // Release elements; no need to flush back
    env->ReleaseDoubleArrayElements( arr, a, JNI_ABORT );
    
    return sum;
}