1 files changed, 7 insertions, 4 deletions

diff --git a/bigint.cpp b/bigint.cpp
index 21c4ab2..9fdafe0 100644
--- a/bigint.cpp
+++ b/bigint.cpp
@@ -133,8 +133,9 @@ Bigint& Bigint::operator=(slongdigit_t v){
 }
 
 Bigint& Bigint::operator+=(const Bigint &o){
-	if(&o==this){
-		return *this=Bigint(*this)+=o;
+	if(&o==this){ //*this + *this
+		operator<<=(1);
+		return *this;
 	}
 	if(sign==1){
 		if(o.sign==1)add(*this,o);
@@ -148,8 +149,10 @@ Bigint& Bigint::operator+=(const Bigint &o){
 }
 
 Bigint& Bigint::operator-=(const Bigint &o){
-	if(&o==this){
-		return *this=Bigint(*this)-=o;
+	if(&o==this){ // *this - *this
+		sign=1;
+		digits.clear();
+		return *this;
 	}
 	if(sign==1){
 		if(o.sign==1)subtract(*this,o);