diff --git a/src/ansi-c/ansi_c_typecheck.cpp b/src/ansi-c/ansi_c_typecheck.cpp
index 50bfe78dffb..02ef8f86de6 100644
--- a/src/ansi-c/ansi_c_typecheck.cpp
+++ b/src/ansi-c/ansi_c_typecheck.cpp
@@ -14,13 +14,9 @@ Author: Daniel Kroening, kroening@kroening.com
 void ansi_c_typecheckt::typecheck()
 {
   start_typecheck_code();
-  for(ansi_c_parse_treet::itemst::iterator
-      it=parse_tree.items.begin();
-      it!=parse_tree.items.end();
-      it++)
-  {
-    typecheck_declaration(*it);
-  }
+
+  for(auto &item : parse_tree.items)
+    typecheck_declaration(item);
 }
 
 bool ansi_c_typecheck(
diff --git a/src/ansi-c/c_typecheck_base.cpp b/src/ansi-c/c_typecheck_base.cpp
index 03170ca8fbe..b420d88cfe5 100644
--- a/src/ansi-c/c_typecheck_base.cpp
+++ b/src/ansi-c/c_typecheck_base.cpp
@@ -143,16 +143,14 @@ void c_typecheck_baset::typecheck_new_symbol(symbolt &symbol)
   {
     if(symbol.value.is_not_nil() &&
        !symbol.is_macro)
+    {
       typecheck_function_body(symbol);
+    }
     else
     {
       // we don't need the identifiers
-      code_typet &code_type=to_code_type(symbol.type);
-      for(code_typet::parameterst::iterator
-          it=code_type.parameters().begin();
-          it!=code_type.parameters().end();
-          it++)
-        it->set_identifier(irep_idt());
+      for(auto &parameter : to_code_type(symbol.type).parameters())
+        parameter.set_identifier(irep_idt());
     }
   }
   else if(!symbol.is_macro)
@@ -361,13 +359,9 @@ void c_typecheck_baset::typecheck_redefinition_non_type(
           old_symbol.is_file_local=new_symbol.is_file_local;
 
           // remove parameter declarations to avoid conflicts
-          const code_typet::parameterst &old_p=old_ct.parameters();
-          for(code_typet::parameterst::const_iterator
-              p_it=old_p.begin();
-              p_it!=old_p.end();
-              p_it++)
+          for(const auto &old_parameter : old_ct.parameters())
           {
-            const irep_idt &identifier=p_it->get_identifier();
+            const irep_idt &identifier = old_parameter.get_identifier();
 
             symbol_tablet::symbolst::const_iterator p_s_it=
               symbol_table.symbols.find(identifier);
@@ -530,31 +524,27 @@ void c_typecheck_baset::typecheck_function_body(symbolt &symbol)
   unsigned anon_counter=0;
 
   // Add the parameter declarations into the symbol table.
-  code_typet::parameterst &parameters=code_type.parameters();
-  for(code_typet::parameterst::iterator
-      p_it=parameters.begin();
-      p_it!=parameters.end();
-      p_it++)
+  for(auto &p : code_type.parameters())
   {
     // may be anonymous
-    if(p_it->get_base_name().empty())
+    if(p.get_base_name().empty())
     {
       irep_idt base_name="#anon"+std::to_string(anon_counter++);
-      p_it->set_base_name(base_name);
+      p.set_base_name(base_name);
     }
 
     // produce identifier
-    irep_idt base_name=p_it->get_base_name();
+    irep_idt base_name = p.get_base_name();
     irep_idt identifier=id2string(symbol.name)+"::"+id2string(base_name);
 
-    p_it->set_identifier(identifier);
+    p.set_identifier(identifier);
 
     parameter_symbolt p_symbol;
 
-    p_symbol.type=p_it->type();
+    p_symbol.type = p.type();
     p_symbol.name=identifier;
     p_symbol.base_name=base_name;
-    p_symbol.location=p_it->source_location();
+    p_symbol.location = p.source_location();
 
     symbolt *new_p_symbol;
     move_symbol(p_symbol, new_p_symbol);
@@ -564,13 +554,12 @@ void c_typecheck_baset::typecheck_function_body(symbolt &symbol)
   typecheck_code(to_code(symbol.value));
 
   // check the labels
-  for(std::map<irep_idt, source_locationt>::const_iterator
-      it=labels_used.begin(); it!=labels_used.end(); it++)
+  for(const auto &label : labels_used)
   {
-    if(labels_defined.find(it->first)==labels_defined.end())
+    if(labels_defined.find(label.first) == labels_defined.end())
     {
-      error().source_location=it->second;
-      error() << "branching label `" << it->first
+      error().source_location = label.second;
+      error() << "branching label `" << label.first
               << "' is not defined in function" << eom;
       throw 0;
     }
@@ -626,12 +615,9 @@ void c_typecheck_baset::apply_asm_label(
   {
     const code_typet &code_type=to_code_type(symbol.type);
 
-    for(code_typet::parameterst::const_iterator
-        p_it=code_type.parameters().begin();
-        p_it!=code_type.parameters().end();
-        ++p_it)
+    for(const auto &p : code_type.parameters())
     {
-      const irep_idt &p_bn=p_it->get_base_name();
+      const irep_idt &p_bn = p.get_base_name();
       if(p_bn.empty())
         continue;
 
@@ -678,12 +664,9 @@ void c_typecheck_baset::typecheck_declaration(
     }
 
     // Now do declarators, if any.
-    for(ansi_c_declarationt::declaratorst::iterator
-        d_it=declaration.declarators().begin();
-        d_it!=declaration.declarators().end();
-        d_it++)
+    for(auto &declarator : declaration.declarators())
     {
-      c_storage_spect full_spec(declaration.full_type(*d_it));
+      c_storage_spect full_spec(declaration.full_type(declarator));
       full_spec|=c_storage_spec;
 
       declaration.set_is_inline(full_spec.is_inline);
@@ -696,7 +679,7 @@ void c_typecheck_baset::typecheck_declaration(
       declaration.set_is_used(full_spec.is_used);
 
       symbolt symbol;
-      declaration.to_symbol(*d_it, symbol);
+      declaration.to_symbol(declarator, symbol);
       current_symbol=symbol;
 
       // now check other half of type
@@ -749,7 +732,7 @@ void c_typecheck_baset::typecheck_declaration(
       }
 
       irep_idt identifier=symbol.name;
-      d_it->set_name(identifier);
+      declarator.set_name(identifier);
 
       typecheck_symbol(symbol);
 
diff --git a/src/ansi-c/c_typecheck_code.cpp b/src/ansi-c/c_typecheck_code.cpp
index e885807f3ce..7bad78eb1e7 100644
--- a/src/ansi-c/c_typecheck_code.cpp
+++ b/src/ansi-c/c_typecheck_code.cpp
@@ -259,12 +259,9 @@ void c_typecheck_baset::typecheck_decl(codet &code)
 
   // iterate over declarators
 
-  for(ansi_c_declarationt::declaratorst::const_iterator
-      d_it=declaration.declarators().begin();
-      d_it!=declaration.declarators().end();
-      d_it++)
+  for(const auto &d : declaration.declarators())
   {
-    irep_idt identifier=d_it->get_name();
+    irep_idt identifier = d.get_name();
 
     // look it up
     symbol_tablet::symbolst::const_iterator s_it=
diff --git a/src/ansi-c/c_typecheck_typecast.cpp b/src/ansi-c/c_typecheck_typecast.cpp
index 2ce03d83f18..09c3f055b96 100644
--- a/src/ansi-c/c_typecheck_typecast.cpp
+++ b/src/ansi-c/c_typecheck_typecast.cpp
@@ -20,33 +20,22 @@ void c_typecheck_baset::implicit_typecast(
 
   c_typecast.implicit_typecast(expr, dest_type);
 
-  for(std::list<std::string>::const_iterator
-      it=c_typecast.errors.begin();
-      it!=c_typecast.errors.end();
-      it++)
+  for(const auto &tc_error : c_typecast.errors)
   {
     error().source_location=expr.find_source_location();
     error() << "in expression `" << to_string(expr) << "':\n"
-            << "conversion from `"
-            << to_string(src_type) << "' to `"
-            << to_string(dest_type) << "': "
-            << *it << eom;
+            << "conversion from `" << to_string(src_type) << "' to `"
+            << to_string(dest_type) << "': " << tc_error << eom;
   }
 
   if(!c_typecast.errors.empty())
     throw 0; // give up
 
-  for(std::list<std::string>::const_iterator
-      it=c_typecast.warnings.begin();
-      it!=c_typecast.warnings.end();
-      it++)
+  for(const auto &tc_warning : c_typecast.warnings)
   {
     warning().source_location=expr.find_source_location();
-    warning() << "warning: conversion from `"
-              << to_string(src_type)
-              << "' to `"
-              << to_string(dest_type)
-              << "': " << *it << eom;
+    warning() << "warning: conversion from `" << to_string(src_type) << "' to `"
+              << to_string(dest_type) << "': " << tc_warning << eom;
   }
 }
 
diff --git a/src/ansi-c/expr2c.cpp b/src/ansi-c/expr2c.cpp
index 9768e61844d..b4abacc3270 100644
--- a/src/ansi-c/expr2c.cpp
+++ b/src/ansi-c/expr2c.cpp
@@ -92,13 +92,11 @@ static std::string clean_identifier(const irep_idt &id)
     dest.erase(0, c_pos+2);
   else if(c_pos!=std::string::npos)
   {
-    for(std::string::iterator it2=dest.begin();
-        it2!=dest.end();
-        ++it2)
-      if(*it2==':')
-        *it2='$';
-      else if(*it2=='-')
-        *it2='_';
+    for(char &ch : dest)
+      if(ch == ':')
+        ch = '$';
+      else if(ch == '-')
+        ch = '_';
   }
 
   // rewrite . as used in ELF section names
@@ -113,20 +111,17 @@ void expr2ct::get_shorthands(const exprt &expr)
   find_symbols(expr, symbols);
 
   // avoid renaming parameters, if possible
-  for(find_symbols_sett::const_iterator
-      it=symbols.begin();
-      it!=symbols.end();
-      it++)
+  for(const auto &symbol_id : symbols)
   {
     const symbolt *symbol;
-    bool is_param=!ns.lookup(*it, symbol) && symbol->is_parameter;
+    bool is_param = !ns.lookup(symbol_id, symbol) && symbol->is_parameter;
 
     if(!is_param)
       continue;
 
-    irep_idt sh=id_shorthand(*it);
+    irep_idt sh = id_shorthand(symbol_id);
 
-    std::string func = id2string(*it);
+    std::string func = id2string(symbol_id);
     func = func.substr(0, func.rfind("::"));
 
     // if there is a global symbol of the same name as the shorthand (even if
@@ -137,19 +132,16 @@ void expr2ct::get_shorthands(const exprt &expr)
 
     ns_collision[func].insert(sh);
 
-    if(!shorthands.insert(std::make_pair(*it, sh)).second)
+    if(!shorthands.insert(std::make_pair(symbol_id, sh)).second)
       UNREACHABLE;
   }
 
-  for(find_symbols_sett::const_iterator
-      it=symbols.begin();
-      it!=symbols.end();
-      it++)
+  for(const auto &symbol_id : symbols)
   {
-    if(shorthands.find(*it)!=shorthands.end())
+    if(shorthands.find(symbol_id) != shorthands.end())
       continue;
 
-    irep_idt sh=id_shorthand(*it);
+    irep_idt sh = id_shorthand(symbol_id);
 
     bool has_collision=
       ns_collision[irep_idt()].find(sh)!=
@@ -168,16 +160,16 @@ void expr2ct::get_shorthands(const exprt &expr)
       irep_idt func;
 
       const symbolt *symbol;
-      if(!ns.lookup(*it, symbol))
+      if(!ns.lookup(symbol_id, symbol))
         func=symbol->location.get_function();
 
       has_collision=!ns_collision[func].insert(sh).second;
     }
 
     if(has_collision)
-      sh=clean_identifier(*it);
+      sh = clean_identifier(symbol_id);
 
-    shorthands.insert(std::make_pair(*it, sh));
+    shorthands.insert(std::make_pair(symbol_id, sh));
   }
 }
 
@@ -1786,13 +1778,10 @@ std::string expr2ct::convert_constant(
     const c_enum_typet::memberst &members=
       to_c_enum_type(c_enum_type).members();
 
-    for(c_enum_typet::memberst::const_iterator
-        it=members.begin();
-        it!=members.end();
-        it++)
+    for(const auto &member : members)
     {
-      if(it->get_value()==int_value_string)
-        return "/*enum*/"+id2string(it->get_base_name());
+      if(member.get_value() == int_value_string)
+        return "/*enum*/" + id2string(member.get_base_name());
     }
 
     // failed...