comp.cpp: In function 'long int sum(std::string)': comp.cpp:11: warning: comparison between signed and unsigned integer expressions comp.cpp: In function 'long int add(std::string)': comp.cpp:26: warning: comparison between signed and unsigned integer expressions comp.cpp:29: warning: comparison between signed and unsigned integer expressions comp.cpp: In function 'int main()': comp.cpp:53: warning: comparison between signed and unsigned integer expressions