Compilare: user.cpp: In function ‘int main()’: user.cpp:17:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=1;j<=strlen(s+1);j++) t[s[j]]++; ^ user.cpp:17:48: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (j=1;j<=strlen(s+1);j++) t[s[j]]++; ^ user.cpp:36:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=1;j<=strlen(s+1);j++){ ^ user.cpp:38:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k=1;k<=strlen(ss+1);k++) ^ user.cpp:8:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("playwithstring.in","r",stdin); ^ user.cpp:9:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("playwithstring.out","w",stdout); ^ user.cpp:10:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:12:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&tip); ^ user.cpp:16:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s+1); bool ok=true; ^ user.cpp:32:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s%s\n",s+1,ss+1); ^ /tmp/cceyDlNl.o: In function `main': user.cpp:(.text.startup+0x1bd): warning: the `gets' function is dangerous and should not be used.