Compilare: main.cpp: In function 'int main()': main.cpp:84:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<strlen(s); i++){ ~^~~~~~~~~~ main.cpp:89:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<strlen(s); j++){ ~^~~~~~~~~~ main.cpp:97:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<strlen(s); j++){ ~^~~~~~~~~~