Compilare: main.cpp: In function 'int main()': main.cpp:96:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<files_ptr.size();i++){ ~^~~~~~~~~~~~~~~~~ main.cpp: In lambda function: main.cpp:109:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a.size();i++){ ~^~~~~~~~~ main.cpp:111:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<a.size()-1) total1+="\\"; ~^~~~~~~~~~~ main.cpp:113:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b.size();i++){ ~^~~~~~~~~ main.cpp:115:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<b.size()-1) total2+="\\"; ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:119:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<full_files.size();i++){ ~^~~~~~~~~~~~~~~~~~ main.cpp:121:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<full_files[i].size()-1;j++){ ~^~~~~~~~~~~~~~~~~~~~~~~