learn operator

.gitignore

@@ -36,3 +36,5 @@
 
 tempCodeRunnerFile
 tempCodeRunnerFile.cpp
+day3/afternoon/test
+day3/afternoon/operator

day3/afternoon/operator.cpp

@@ -0,0 +1,17 @@
+#include <bits/stdc++.h>
+using std::cout,std::cin,std::vector,std::endl;
+
+std::ostream& operator<<(std::ostream& os,vector<int> &v){
+    os<<"vector<int> [";
+    for(size_t i=0;i<v.size();i++){
+        os<<v[i]<<(i!=v.size()-1?",":"]\n");
+    }
+    return os;
+}
+
+int main(){
+    vector<int> v;
+    v.push_back(1);
+    v.push_back(2);
+    cout<<v<<endl;
+}