Compilare: user.cpp: In function ‘int main()’: user.cpp:41:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<=strlen(s)-1;i++){ ^ user.cpp:55:31: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] aux[nrl+1]=NULL; ^ user.cpp:77:31: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] aux[nrl+1]=NULL; ^ user.cpp:102:31: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] aux[nrl+1]=NULL; ^ user.cpp:123:23: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] aux[nrl+1]=NULL; ^ user.cpp:137:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<=strlen(a[i])-1;j++) ^ user.cpp:8:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("reteta2.in","r",stdin); ^ user.cpp:9:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("reteta2.out","w",stdout); ^ user.cpp:11:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccIQWIEI.o: In function `main': user.cpp:(.text.startup+0x56): warning: the `gets' function is dangerous and should not be used.