Compilare: main.cpp: In function 'void pre()': main.cpp:10:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(s1)) ~^~~~~~~~~~~ main.cpp:12:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s1[i]==s1[j]&&i<strlen(s1)) ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:24:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(s2);i++) ~^~~~~~~~~~~ main.cpp:30:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j==strlen(s1)) ~^~~~~~~~~~~~