/in/foo.cc: In function 'int main()':
/in/foo.cc:16:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i=0;i<a1.size();i++){
~^~~~~~~~~~
/in/foo.cc:24:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i=0;i<b1.size();i++){
~^~~~~~~~~~
/in/foo.cc:35:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (i=0;i<a1.size();i++){
~^~~~~~~~~~
/in/foo.cc:41:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (i=0;i<b1.size();i++){
~^~~~~~~~~~