Read alpharithmetic binary data using fstreams

//this function takes a reference to the file input stream and the number of characters to read from the file
string fread_char(ifstream &input_file,int no_characters) {
 
    char temp[no_characters]; //initially we create an appropriately sized 'char' array
    input_file.read(temp,(no_characters)*sizeof(char));//we read the characters. note how we specify the number of bytes
    string str(temp); //we convert the 'char' array to a string and return it
    return str;
}
 
ifstream input_data;
input_data.open("input.dat",ios::in | ios::binary); //note the modifiers that denote both input file and binary mode
reg_name=fread_char(input_data,name_length);