friends.cpp: In function 'int main()':
friends.cpp:27:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(S1.size()+S2.size()==A)
^
friends.cpp:38:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(S1.size()+S2.size()==A)
^
friends.cpp:56:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(S3.size()+S2.size()==A)
^
friends.cpp:67:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(S3.size()+S2.size()==A)
^
friends.cpp:75:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(S1!=S3 && S1.size() == A && S3.size() == A)
^
friends.cpp:75:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(S1!=S3 && S1.size() == A && S3.size() == A)
^
friends.cpp:77:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
else if(S1.size()==A){
^
friends.cpp:80:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
else if(S3.size()==A){
^
friends.cpp:8:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&N);
^