Append an int to a std string

Question

Why is this code gives an Debug Assertion Fail      std  string query     int ClientID   666     query    select logged from login where id         query append  char   ClientID

User · Answer

I have a feeling that your ClientID is not of a string type  zero-terminated char  or std  string  but some integral type  e g  int  so you need to convert number to the string first   std  stringstream ss  ss  lt  lt  ClientID  query append ss str       But you can use operator  as well  instead of append    query    ss str

User · Answer

You cannot cast an int to a char  to get a string   Try this   std  ostringstream sstream  sstream  lt  lt   select logged from login where id      lt  lt  ClientID  std  string query   sstream str      stringstream reference

User · Answer

The std  string  append   method expects its argument to be a NULL terminated string  char     There are several approaches for producing a string containg an int    std  ostringstream   include  lt sstream gt   std  ostringstream s  s  lt  lt   select logged from login where id      lt  lt  ClientID  std  string query s str      std  to string  C  11   std  string query  select logged from login where id                         std  to string ClientID     boost  lexical cast   include  lt boost lexical cast hpp gt   std  string query  select logged from login where id                         boost  lexical cast lt std  string gt  ClientID

User · Answer

You are casting ClientID to char  causing the function to assume its a null terinated char array  which it is not   from cplusplus com        string amp  append   const char   s    Appends a copy of the string formed   by the null-terminated character sequence  C string  pointed by s  The   length of this character sequence is determined by the first ocurrence   of a null character  as determined by traits length s

[c++] Append an int to a std::string

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