HelloWorld_switch.c

#include <switch.h>
#include <stdio.h>

int main(int argc, char** argv) {
    u32 kdown = 0x00000000;
    u32 kdownOld = 0x00000000;

    gfxInitDefault();
    consoleInit(nullptr); //Init the console

    while(appletMainLoop()) {
        hidScanInput();    //Scan for input       
        kdown = hidKeysDown(CONTROLLER_P1_AUTO); //Read the currently pressed buttons and store that value into kdown

         //Edge detection. We don't want to print "Hello World" while A is pressed. We only want to print it once and then again on the next press
        if(kdown > kdownOld) {
            if(kdown & KEY_A)
                printf("Hello World\n"); //Prints to the console on screen
        }

        kdownOld = kdown;
         
        gfxFlushBuffers();   //Finish this frame
        gfxSwapBuffers();    //Display it on the screen
        gfxWaitForVsync();   //Wait till the last frame finished displaying before updating to avoid flickering
    }
    gfxExit();
    return 0;
}