Compilare: user.cpp: In function ‘int conversnr(int&)’: user.cpp:19:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( ;i<inp.size()&&isdigit(inp[i]);i++) ^ user.cpp: In function ‘void conversrpn()’: user.cpp:38:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<inp.size();i++) ^ user.cpp:61:48: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(!c.empty()&&p[c.top()]>=p[inp[i]]) ^ user.cpp:61:59: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(!c.empty()&&p[c.top()]>=p[inp[i]]) ^ user.cpp: In function ‘int main()’: user.cpp:85:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^