std::string as struct member variable

below is the problem !!!

Hi have this code Expand|Select|Wrap|Line Numbers struct SF { std::string mnemonic;//mnemonic that represents it std::string name;//a descriptive name ushort num_val1;// number of the first value uchar possiblevalues_num; //number of the possible values. uchar type; /* = 1 if the feature is utilized in the models*/ }; basically i am trying to declare a std::string object in a struct to later fill it with information the next step i allocate an array of SF structs and try to do it Expand|Select|Wrap|Line Numbers SF * FTab; FTab = (SF *) calloc(6, sizeof(SF)); FTab[0].num_val1 = (ushort) 5; FTab[0].mnemonic("xpto"); the ushort type i can acess, the std::string generates a segmentation fault error, and i can't understant why. Does anyone know what i am doing wrong? PS- sorry for the bad english.

Below is solution

weaknessforcats E M M Join Date: Mar 2007 Location: North Bend Washington USA Posts: 6,292 #2: Oct 16 '07

re: std::string as struct member variable It's the call to calloc. C++ uses constructors and destructors to initialize and clean up objects. calloc doesn't know about this so never called them. Your string members are garbage. Do not use C memory allocation in C++. Use only new an delete. Here is the corrected code: Expand|Select|Wrap|Line Numbers struct SF { std::string mnemonic;//mnemonic that represents it std::string name;//a descriptive name unsigned short num_val1;// number of the first value unsigned char possiblevalues_num; //number of the possible values. unsigned char type; /* = 1 if the feature is utilized in the models*/ }; int main() { SF * FTab; FTab = new SF[5]; FTab[0].num_val1 = 5; FTab[0].mnemonic ="xpto"; } Decide now whether you will write in C++ or not. If yes, then do not: 1) malloc, calloc, alloc, etc..... 2) memcpy, mem... anything 3) free 4) exit(1) 5) strcpy, str... anything for openers.