File content as of revision 0:c0fd2733e2bb:

#include "mbed.h"

//------------------------------------
// Hyperterminal configuration
// 9600 bauds, 8-bit data, no parity
//------------------------------------

Serial pc(SERIAL_TX, SERIAL_RX);
char username[8];
char userkey;
DigitalOut myled(LED1);

int main(){
    myled=1;
    
    pc.printf("Hello World,please enter you name to continue\r\n");

    pc.scanf("%s",username);

    pc.printf("Hello %s,please enter return to continue\r\n",username);
    
    while (pc.readable())
    
        pc.getc();
        
    while (1){
        
        userkey=pc.getc();
        
        if (userkey=='a'){
            
            for (int j=0;j<3;j++){
            
                myled=1;
            
                wait(1);
            
                myled=0;
            
                wait(1);
            }
            
            break;
            
        } 
            
        else
        
        pc.printf("Wrong key,please enter return key to continue \r\n");
    
    }
    
    pc.printf("Right key,Good Bye \r\n");
    
}