Having a problem with pass by reference in two dimensional array in c++ -

i have variable called names 2 dimensional array. declared below there maximum of 5 names , each name consist of 256 characters.

int main(){     char names[5][256];     strcpy(names[0],"john");     strcpy(names[1],"matt");     printf("%d\n",sizeof(names)/256);        //this prints out 5 correct     passit(names);              }  void passit(char names[][256]){     printf("%d\n",sizeof(names)/256);        //this prints out 8 seems size of pointer }  

how should change in passit function, number of elements printed correctly?

your code c-style. if you're writing c++ suggest using std::cout, std::vector , std::string:

void passit(std::vector<std::string> const& names) {     std::cout << names.size(); }   int main() {     std::vector<std::string> names(5);     names[0] = "john";     names[1] = "matt";      std::cout << names.size();     passit(names);              } 

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otherwise, can perform intermediate fix existing code.

as you've spotted, when try pass array value decays pointer (char(*)[256] in case) , lose information on size of first dimension.

passing array reference avoids this, except have specify full array type including array dimensions; template argument deduction makes automatic:

template <size_t n> void passit(char (&names)[n][256]) {     printf("%d\n", n); }