Remove redundant string initialisation

Both std::string and dstringt are default-initialised to an empty string.

jbmc/src/java_bytecode/expr2java.cpp

@@ -277,7 +277,7 @@ std::string expr2javat::convert_rec(
     // so we make one up, loosely inspired by the syntax
     // of lambda expressions.
 
-    std::string dest="";
+    std::string dest;
 
     dest+='(';
     const java_method_typet::parameterst &parameters = method_type.parameters();

src/analyses/local_may_alias.cpp

@@ -458,7 +458,7 @@ void local_may_aliast::output(
           if(loc_info.aliases.find(j)==i)
           {
             assert(j<objects.size());
-            irep_idt identifier = "";
+            irep_idt identifier;
             if(objects[j].id() == ID_symbol)
               identifier = to_symbol_expr(objects[j]).get_identifier();
             out << ' ' << from_expr(ns, identifier, objects[j]);

src/cpp/cpp_typecheck_resolve.cpp

@@ -872,7 +872,7 @@ cpp_scopet &cpp_typecheck_resolvet::resolve_scope(
     recursive=false;
   }
 
-  std::string final_base_name="";
+  std::string final_base_name;
   template_args.make_nil();
 
   while(pos!=cpp_name.get_sub().end())

src/goto-analyzer/show_on_source.cpp

@@ -58,7 +58,7 @@ static void print_with_indent(
 {
   const std::size_t p = indent_line.find_first_not_of(" \t");
   const std::string indent =
-    p == std::string::npos ? std::string("") : std::string(indent_line, 0, p);
+    p == std::string::npos ? std::string() : std::string(indent_line, 0, p);
   std::istringstream in(src);
   std::string src_line;
   while(std::getline(in, src_line))

src/goto-instrument/dot.cpp

@@ -104,7 +104,7 @@ void dott::write_dot_subgraph(
       if(it==instructions.end() ||
          seen.find(it)!=seen.end()) continue;
 
-      std::stringstream tmp("");
+      std::stringstream tmp;
       if(it->is_goto())
       {
         if(it->get_condition().is_true())

src/goto-instrument/dump_c_class.h

@@ -71,7 +71,6 @@ protected:
 
     explicit typedef_infot(const irep_idt &name):
       typedef_name(name),
-      type_decl_str(""),
       early(false)
     {
     }

src/goto-instrument/goto_program2code.cpp

@@ -1864,7 +1864,7 @@ void goto_program2codet::cleanup_expr(exprt &expr, bool no_typecast)
       // Replace by a function call to nondet_...
       // We first search for a suitable one in the symbol table.
 
-      irep_idt id="";
+      irep_idt id;
 
       for(symbol_tablet::symbolst::const_iterator
           it=symbol_table.symbols.begin();
@@ -1888,7 +1888,7 @@ void goto_program2codet::cleanup_expr(exprt &expr, bool no_typecast)
 
       if(id.empty())
       {
-        irep_idt base_name="";
+        irep_idt base_name;
 
         if(expr.type().get(ID_C_c_type)!="")
         {

src/goto-programs/string_abstraction.cpp

@@ -949,7 +949,7 @@ bool string_abstractiont::build_symbol(const symbol_exprt &sym, exprt &dest)
   const typet &abstract_type=build_abstraction_type(symbol.type);
   CHECK_RETURN(!abstract_type.is_nil());
 
-  irep_idt identifier="";
+  irep_idt identifier;
 
   if(current_args.find(symbol.name)!=current_args.end())
     identifier=id2string(symbol.name)+arg_suffix;

src/solvers/qbf/qbf_qube.cpp

@@ -55,7 +55,7 @@ propt::resultt qbf_qubet::prop_solve()
     write_qdimacs_cnf(out);
   }
 
-  std::string options="";
+  std::string options;
 
   // solve it
   int res=system(

src/solvers/qbf/qbf_qube_core.cpp

@@ -51,7 +51,7 @@ propt::resultt qbf_qube_coret::prop_solve()
     write_qdimacs_cnf(out);
   }
 
-  std::string options="";
+  std::string options;
 
   // solve it
   int res=system((

src/solvers/qbf/qbf_skizzo.cpp

@@ -55,7 +55,7 @@ propt::resultt qbf_skizzot::prop_solve()
     write_qdimacs_cnf(out);
   }
 
-  std::string options="";
+  std::string options;
 
   // solve it
   int res=system((

src/solvers/qbf/qbf_skizzo_core.cpp

@@ -68,7 +68,7 @@ propt::resultt qbf_skizzo_coret::prop_solve()
     write_qdimacs_cnf(out);
   }
 
-  std::string options="";
+  std::string options;
 
   // solve it
   system((

src/util/string_utils.cpp

@@ -138,7 +138,7 @@ std::string trim_from_last_delimiter(
   const std::string &s,
   const char delim)
 {
-  std::string result="";
+  std::string result;
   const size_t index=s.find_last_of(delim);
   if(index!=std::string::npos)
     result=s.substr(0, index);

src/util/xml.cpp

@@ -213,7 +213,7 @@ void xmlt::set_attribute(
 /// \return the unescaped string
 std::string xmlt::unescape(const std::string &str)
 {
-  std::string result("");
+  std::string result;
 
   result.reserve(str.size());
 

unit/json_symbol_table.cpp

@@ -59,7 +59,7 @@ void get_goto_model(std::istream &in, goto_modelt &goto_model)
   language_filest language_files;
   language_files.set_message_handler(null_message_handler);
 
-  std::string filename("");
+  std::string filename;
 
   language_filet &language_file = language_files.add_file(filename);
 

unit/solvers/strings/string_constraint_generator_valueof/calculate_max_string_length.cpp

@@ -16,7 +16,7 @@ Author: Diffblue Ltd.
 /// given radix.
 static size_t expected_length(unsigned long radix, const typet &type)
 {
-  std::string longest("");
+  std::string longest;
   if(radix == 2)
   {
     if(type == unsignedbv_typet(32))

unit/util/string_utils/split_string.cpp

@@ -107,7 +107,7 @@ SCENARIO("split_string", "[core][utils][string_utils][split_string]")
   }
   GIVEN("An empty string")
   {
-    std::string string = "";
+    std::string string;
     WHEN("Splitting it")
     {
       expected_resultst expected_results;