/in/foo.cc: In function 'int main()':
/in/foo.cc:24:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if (s1[0]!='-') s1='+'+s1; if (s2[0]!='-') s2='+'+s2;
  ^~
/in/foo.cc:24:29: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
  if (s1[0]!='-') s1='+'+s1; if (s2[0]!='-') s2='+'+s2;
                             ^~
/in/foo.cc:26:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(k<s1.size())
        ~^~~~~~~~~~
/in/foo.cc:31:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(s1[k]!='+'&&s1[k]!='-'&&k<s1.size()) 
                                  ~^~~~~~~~~~
/in/foo.cc:38:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(k<s2.size())
        ~^~~~~~~~~~
/in/foo.cc:43:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(s2[k]!='+'&&s2[k]!='-'&&k<s2.size()) 
                                  ~^~~~~~~~~~
/in/foo.cc:54:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(j=1;j<ss[i].size()-1;j++) t=t*10+(ss[i][j]-48);
            ~^~~~~~~~~~~~~~~
/in/foo.cc:61:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(j=1;j<ss[i].size();j++) t=t*10+(ss[i][j]-48);
            ~^~~~~~~~~~~~~
/in/foo.cc:17:8: warning: unused variable 'n' [-Wunused-variable]
  int i,n,t,j,k,x=0,m=0,l=0; string s,s1,s2;
        ^