Compilare: user.cpp: In function ‘void first()’: user.cpp:24:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(start<strlen(c)-1) ^ user.cpp:61:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(start<strlen(c)-1) ^ user.cpp: In function ‘void update()’: user.cpp:99:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<strlen(c)-1;i++) ^ user.cpp: In function ‘int getMax()’: user.cpp:111:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<strlen(c);i++) ^