You can use a diff editor from Qt Creator to compare two text files. They can be either versions of the same file or arbitrary files.

To compare files:

1. Select Tools > Diff.
2. Select two files to compare.

The differences are output in the Edit mode. Color coding is used to mark changed lines. By default, light red indicates lines that contain removed text (painted a darker red) in the left pane and light green indicates lines that contain added text (painted a darker green) in the right pane.

To view the differences in a unified view where changed rows are placed below each other, select (Switch to Unified Diff Editor).

To switch back to the side-by-side view, select (Switch to Side by Side Diff Editor).

To change the default colors, select Tools > Options > Text Editor > Font & Colors. Create your own color scheme and select new colors for the following options:

• Diff File Line sets the color of the line that shows the path and filename of the changed file.
• Diff Context Line sets the color of the line that shows the number of hidden lines between changed lines.
• Diff Source Line sets the color of lines that contain removed text.
• Diff Source Character sets the color that indicates removed characters.
• Diff Destination Line sets the color of lines that contain added text.
• Diff Destination Character sets the color that indicates added characters.

To only show text changes, select Ignore Whitespace.

To expand the context for the changes, set the number of unchanged lines to show in Context lines. Set the value to -1 to show the whole file.

By default, the horizontal scroll bars in the left and right pane are synchronized. To use them independently of each other, select the (Synchronize Horizontal Scroll Bars) button.

If the files change outside Qt Creator, select (Reload Editor) to compare them again and to show the results.