List of reserved words in C

     auto d                       if
    break                        int d
    case                         long d
    char d                   register d
    continue                     return
    default                      short d
    do                           sizeof
    double d                 static d
    else                         struct
    entry                        switch
    extern d                 typedef d
    float d                  union d
    for                          unsigned d
    goto                         while

    also in modern implementations:

    enum d
    void d

    const d
    signed d
    volatile d