Remove useless string initialization.

src/netbase.cpp

@@ -139,7 +139,7 @@ bool Lookup(const char *pszName, std::vector<CService>& vAddr, int portDefault,
     if (pszName[0] == 0)
         return false;
     int port = portDefault;
-    std::string hostname = "";
+    std::string hostname;
     SplitHostPort(std::string(pszName), port, hostname);
 
     std::vector<CNetAddr> vIP;

src/rest.cpp

@@ -90,7 +90,7 @@ static enum RetFormat ParseDataFormat(std::string& param, const std::string& str
 
 static std::string AvailableDataFormatsString()
 {
-    std::string formats = "";
+    std::string formats;
     for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
         if (strlen(rf_names[i].name) > 0) {
             formats.append(".");

src/test/net_tests.cpp

@@ -171,7 +171,7 @@ BOOST_AUTO_TEST_CASE(cnode_simple_test)
     ipv4Addr.s_addr = 0xa0b0c001;
     
     CAddress addr = CAddress(CService(ipv4Addr, 7777), NODE_NETWORK);
-    std::string pszDest = "";
+    std::string pszDest;
     bool fInboundIn = false;
 
     // Test that fFeeler is false by default.

src/utilstrencodings.cpp

@@ -127,7 +127,7 @@ std::string EncodeBase64(const unsigned char* pch, size_t len)
 {
     static const char *pbase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
-    std::string strRet = "";
+    std::string strRet;
     strRet.reserve((len+2)/3*4);
 
     int mode=0, left=0;
@@ -267,7 +267,7 @@ std::string EncodeBase32(const unsigned char* pch, size_t len)
 {
     static const char *pbase32 = "abcdefghijklmnopqrstuvwxyz234567";
 
-    std::string strRet="";
+    std::string strRet;
     strRet.reserve((len+4)/5*8);
 
     int mode=0, left=0;

src/wallet/rpcdump.cpp

@@ -279,7 +279,7 @@ UniValue importaddress(const JSONRPCRequest& request)
         );
 
 
-    std::string strLabel = "";
+    std::string strLabel;
     if (!request.params[1].isNull())
         strLabel = request.params[1].get_str();
 
@@ -452,7 +452,7 @@ UniValue importpubkey(const JSONRPCRequest& request)
         );
 
 
-    std::string strLabel = "";
+    std::string strLabel;
     if (!request.params[1].isNull())
         strLabel = request.params[1].get_str();