Pass const QString by reference instead of by value

src/xlsx/xlsxdocument.cpp

@@ -113,7 +113,7 @@ Format *Document::createFormat()
 /*!
  * Write \a value to cell \a row_column with the \a format.
  */
-int Document::write(const QString row_column, const QVariant &value, Format *format)
+int Document::write(const QString &row_column, const QVariant &value, Format *format)
 {
     return currentWorksheet()->write(row_column, value, format);
 }

src/xlsx/xlsxdocument.h

@@ -53,7 +53,7 @@ public:
     ~Document();
 
     Format *createFormat();
-    int write(const QString cell, const QVariant &value, Format *format=0);
+    int write(const QString &cell, const QVariant &value, Format *format=0);
     int write(int row, int col, const QVariant &value, Format *format=0);
     int insertImage(int row, int column, const QImage &image, double xOffset=0, double yOffset=0, double xScale=1, double yScale=1);
     int mergeCells(const QString &range);

src/xlsx/xlsxworksheet.cpp

@@ -326,7 +326,7 @@ int Worksheet::write(int row, int column, const QVariant &value, Format *format)
 }
 
 //convert the "A1" notation to row/column notation
-int Worksheet::write(const QString row_column, const QVariant &value, Format *format)
+int Worksheet::write(const QString &row_column, const QVariant &value, Format *format)
 {
     QPoint pos = xl_cell_to_rowcol(row_column);
     if (pos == QPoint(-1, -1)) {

src/xlsx/xlsxworksheet.h

@@ -50,7 +50,7 @@ class Q_XLSX_EXPORT Worksheet
 {
     Q_DECLARE_PRIVATE(Worksheet)
 public:
-    int write(const QString row_column, const QVariant &value, Format *format=0);
+    int write(const QString &row_column, const QVariant &value, Format *format=0);
     int write(int row, int column, const QVariant &value, Format *format=0);
     int writeString(int row, int column, const QString &value, Format *format=0);
     int writeInlineString(int row, int column, const QString &value, Format *format=0);