问Android Rot13算法不工作；同样的算法与gcc的作品伟大的想法？

EN

#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "FOO", __VA_ARGS__))

jbyteArray Java_NativeUtils_foo(JNIEnv* env, jobject obj, jstring item)
{
  int upper, i, a, c;
    char p[9];
    const char *d;

    //char *p = item;
    const char *s = (*env)->GetStringUTFChars(env, item, 0);
    //len = (*env)->GetStringUTFLength(env, item);
    //** make a copy
    strncpy(p, s, 8);
    p[8] = '\0';
    (*env)->ReleaseStringUTFChars(env, item, s);
    LOGI("GG1");
    LOGI(p);

    for (i=0; p[i] != 0; i++) {
      LOGI("GG2");
      a =~ (int)p[i];

      c = ~a-1 / ( ~(a|32) / 13*2-11 ) * 13;
      p[i] = (char)c;
      //** for log output
      d = (const char *)&c;
      LOGI(d);
    }

    LOGI("GG3");
    LOGI(p);

    //** convert back to a Java type
    jbyteArray out = (*env)->NewByteArray(env, 8);
    (*env)->SetByteArrayRegion(env, out, 0, 8, (jbyte *)p);
    LOGI("GG4");
    LOGI(out);

    return out;
}

    ( 3521): GG1
    ( 3521): 12345693
    ( 3521): GG2
    ( 3521): 1
    ( 3521): GG2
    ( 3521): 2
    ( 3521): GG2
    ( 3521): 3
    ( 3521): GG2
    ( 3521): 4
    ( 3521): GG2
    ( 3521): 5
    ( 3521): GG2
    ( 3521): 6
    ( 3521): GG2
    ( 3521): 9
    ( 3521): GG2
    ( 3521): 3
    ( 3521): GG3
    ( 3521): 12345693
    ( 3521): GG4
    ( 3521): ??
   -( 3521): Rot13 in:12345693... out:12345693... 

 #include <stdio.h>
    #include <string.h>


    main(int argc, char** argv) {
      int upper, i, a, c;
      char p[9];
      char *in;


      in = argv[1];

      strncpy(p, in, 8);
      p[8] = '\0';
      printf("in ...%s... p ...%s...", in, p);

      for (i=0; p[i] != 0; i++) {
        a =~ (int)p[i];
        c = (~a-1 / ( ~(a|32) / 13*2-11 ) * 13);
        p[i] = (char)c;
      }

      printf("out ...%s...", p);

      //while(a=~getchar())putchar(~a-1/(~(a|32)/13*2-11)*13);}
    }