c++ - Template function return type deduction in C++03 -

i implement following in c++03:

template <typename t1, typename t2> t1 convert(bool condition, t2& value) {     return condition ? value : conversionfunction(value); } 

except call convert without having explicitly specify t1. how do that?

perhaps use hack. hack defer conversion until use return value. return value helper object allows converted else.

template <typename t> struct converthack {     t &value_;     const bool cond_;     converthack (bool cond, t &value) : value_(value), cond_(cond) {}     template <typename u> operator u () const {         return cond_ ? value_ : conversionfunction(value_);     } };  template <typename t> converthack<t> convert(bool condition, t& value) {     return converthack<t>(condition, value); }