cout字符串和c_str在c ++中给出不同的值

Question

In my code, I have a string variable named ChannelPacket. when I print Channelpacket in gdb, it gives following string : "\\020\\000B\\001\\237\\246&\\b\\000\\016\\000\\002\\064\\001\\000\\000\\005\\000\\021\\002\\000\\000\\006\\000\\f\\001\\001\\000\\000sZK"

But if i print Channelpacket.c_str(), it gives just "\\020 output. Please help me.

Answer 1

c_str() returns a pointer to char that's understood to be terminated by a NUL character ( '\\0' ).

Since your string contains an embedded '\\0' , it's seen as the end of the string when viewed as a pointer to char.

When viewed as an actual std::string , the string's length is known, so the whole thing is written out, regardless of the embedded NUL characters.

Answer 2

The second byte is a zero, which means the end of the string. If you want to output the raw bytes, rather than treating them as a null-terminated string, you can't use cout << Channelpacket.c_str() - use cout << Channelpacket instead.