1  // Purpose.  Java calling C
 2  //           (Java passes String in, C returns String)
   
   
 3  ////////////////////////////// JNIdemos.java \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
   
 4  class JNIdemos {
 5     public native static String toUpper( String in );
 6     static {
 7        System.loadLibrary( "JNIdemos" );
 8     }
 9     public static void main( String[] args ) {
10        System.out.println( "upper is " + toUpper( args[0] ) );
11     }
12  }
   
   
13  ////////////////////////////// JNIdemos.cpp \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
   
14  #include <iostream.h>
15  #include <string.h>
16  #include "JNIdemos.h"
   
17  extern "C" {
18  JNIEXPORT jstring JNICALL Java_JNIdemos_toUpper(
19                                          JNIEnv* env, jclass, jstring in ) {
20     const char* inToChar = env->GetStringUTFChars( in, 0 );
21     char*       buf      = new char[strlen(inToChar) + 1];
22     jstring     ret;
23     cout << "input is " << inToChar << endl;
24     for (int i=0; i < strlen(inToChar); i++)
25        buf[i] = (inToChar[i] > 96 && inToChar[i] < 123) ?
26                                          inToChar[i]-32 : inToChar[i];
27     ret = env->NewStringUTF( buf );
28     env->ReleaseStringUTFChars( in, inToChar );
29     delete buf;
30     return ret;
31  }
32  }
   
   
33  // C:> java JNIdemos "Here is CamelCase, with punctuation."
34  // input is Here is CamelCase, with punctuation.
35  // upper is HERE IS CAMELCASE, WITH PUNCTUATION.