foo.cc: In function 'int main()':
foo.cc:11:8: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(c);
        ^
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:14:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (i = 0; i <= strlen(c); i++) {
              ~~^~~~~~~~~~~~
foo.cc:17:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (i = 1; i < strlen(c); i++) {
              ~~^~~~~~~~~~~
foo.cc:18:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (j = 0; j < strlen(c) - 1; j++) {
               ~~^~~~~~~~~~~~~~~
foo.cc:24:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (i = 0; i < strlen(c); i++) {
              ~~^~~~~~~~~~~
foo.cc:25:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (j = 0; j < strlen(c); j++) {
               ~~^~~~~~~~~~~
foo.cc:30:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (i = 0; i < strlen(c); i++) {
              ~~^~~~~~~~~~~
foo.cc:11:6: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
  gets(c);
  ~~~~^~~
/tmp/ccGxQu0e.o: In function `main':
foo.cc:(.text.startup+0x3d): warning: the `gets' function is dangerous and should not be used.

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