foo.cc: In function 'int main()':
foo.cc:7:8: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(a);
        ^
In file included from /usr/include/stdio.h:862:0,
                 from /usr/include/c++/7/cstdio:42,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:46,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:232:1: note: declared here
 gets (char *__str)
 ^~~~
foo.cc:8:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int x = 0; x < strlen(a); x++) {
                  ~~^~~~~~~~~~~
foo.cc:14:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < strlen(a); i++) {
                  ~~^~~~~~~~~~~
foo.cc:26:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int y = 0; y < strlen(a); y++) {
                  ~~^~~~~~~~~~~
foo.cc:7:6: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
  gets(a);
  ~~~~^~~
foo.cc:13:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &k);
  ~~~~~^~~~~~~~~~
/tmp/ccw5Ss9J.o: In function `main':
foo.cc:(.text.startup+0x2c): warning: the `gets' function is dangerous and should not be used.

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