Compilare: main.cpp: In function 'int main()': main.cpp:14:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<strlen(s);i++){ ~^~~~~~~~~~ main.cpp:22:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(s);i++){ ~^~~~~~~~~~ main.cpp:23:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<strlen(s);j++) ~^~~~~~~~~~