Compilare: user.cpp: In function ‘int main()’: user.cpp:12:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<strlen(s);i++) ^ user.cpp:21:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<strlen(s);i++) if ((s[i-1]==')')&&s[i]>=48&&s[i]<=57) ^ user.cpp:29:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<strlen(s);i++) if (strchr("()",s[i-1])!=NULL&&s[i]>=48&&s[i]<=57) ^ user.cpp:38:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<strlen(s);i++) if (strchr("()",s[i])!=NULL) ^ user.cpp:69:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i>=strlen(p)) break; ^