Compilare: main.cpp: In function 'int main()': main.cpp:12:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] {for(i=0;i<strlen(x);i++) ~^~~~~~~~~~ main.cpp:18:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] {for(i=0;i<strlen(x);i++) ~^~~~~~~~~~ main.cpp:24:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] {for(i=0;i<strlen(x);i++) ~^~~~~~~~~~