How to compile C into an executable binary file and run it in Android from Android Shell?

First, let me say that my answer is dependent on your using NDK r7b (it'll work for r7c as well) on Linux (change paths appropriately for other systems).

Edit: Last tested with NDK r8e on Linux and Nexus 4 with adb from SDK Platform-Tools Rev 18 on Windows 7 (latest as of 2013-07-25) without root access.

Yet Another Edit: Please read this question for altering my instruction for native binaries that need to run on Android 5.0(Lollypop) and later.

1. Go to $NDK_ROOT (The topmost folder of NDK zip when unzipped).
2. Copy $NDK_ROOT/samples/hello-jni directory as $NDK_ROOT/sources/hello-world.
3. Go to $NDK_ROOT/sources/hello-world.
4. Edit AndroidManifest.xml to give the application an appropriate name (This is optional).
5. Go to $NDK_ROOT/sources/hello-world/jni. This is where the source code is.
6. Edit hello-jni.c, remove all the code, and put in your hello world code. Mine is:

   #include int main( int argc, char* argv[]){    printf("Hello, World!");    return 0;}

7. Edit Android.mk and change the line include $(BUILD_SHARED_LIBRARY) to include $(BUILD_EXECUTABLE). You can also change the LOCAL_MODULE line to the name you want for your executable(default is hello-jni)
8. Go back to $NDK_ROOT/sources/hello-world
9. Run ../../ndk-build to create the executable.
10. Copy it from $NDK_ROOT/sources/hello-jni/libs/armeabi/hello-jni to /data/local/tmp on the Android device and change it's permissions to 755 (rwxr-xr-x). If you changed the LOCAL_MODULE line in $NDK_ROOT/sources/hello-world/jni/Android.mk, the executable name will be the new value of LOCAL_MODULE instead of hello-jni. (All this is done via adb from the Android SDK.)
11. Execute the binary with full path as /data/local/tmp/hello-jni, or whatever you named it to.

And you're done( and free to start on the documentation in $NDK_ROOT/docs to get a better idea of what to do).

The best/easiest place to put a executable is /data/local. You'll also need to chmod the binary as executable. Often you'll also need to do this in two steps to get the binary from /sdcard/ to /data/local:

$ adb push mybin /sdcard/$ adb shell$ cp /sdcard/mybin /data/local/mybin$ cd /data/local$ chmod 751 mybin

Caveats:

• Not all systems have cp. You can use cat if this is the case:

  $ cat /sdcard/mybin > /data/local/mybin

• Some systems don't allow write in /data/local for the "shell" user. Try /data/local/tmp

the "/sdcard" location is not executable, meaning that any file there is not executable at all.

the only way to "adb push" executable would be to put them in "/data/local", which should be writable for adb, and allow execution for anyone.