error: conversion from ‘long int’ to non-scalar type ‘std::ifstream’ {aka ‘std::basic_ifstream

std::ifstream logfptemp = NULL; For assigning ifstream to null getting above error can't we assign to null?? I am getting it as a error : conversion from ‘long int’ to non-scalar type ‘std::ifstream’ {aka ‘std::basic_ifstream’} requested
where as in c i think we can assign to null.