Add the offset, not subtract.

diff --git a/src/fastq-qualadj.c b/src/fastq-qualadj.c
index 2bfa31fd53b2e971ace097d5c41004fd066f5e17..488fdade28e41dbba7f887f8fd3680d740656563 100644 (file)
--- a/src/fastq-qualadj.c
+++ b/src/fastq-qualadj.c
@@ -51,7 +51,7 @@ void fastq_qualadj(FILE* fin, FILE* fout, int offset)
 
     while (fastq_next(fqf, seq)) {
         for (i = 0; i < seq->qual.n; ++i) {
-            c = (int) seq->qual.s[i] - offset;
+            c = (int) seq->qual.s[i] + offset;
             c = c < 0 ? 0 : (c > 126 ? 126: c);
             seq->qual.s[i] = (char) c;
         }