/in/foo.c: In function 'main':
/in/foo.c:9:19: error: 'perimeter' undeclared (first use in this function)
    9 |                   perimeter=a+b+c;
      |                   ^~~~~~~~~
/in/foo.c:9:19: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:8:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
    8 |     if(a+b>c&&a+c>b&&b+c>a)
      |     ^~
/in/foo.c:10:19: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   10 |                   printf("%.2f\n",perimeter);
      |                   ^~~~~~
/in/foo.c: At top level:
/in/foo.c:11:11: error: expected identifier or '(' before 'else'
   11 |         } else {
      |           ^~~~
/in/foo.c:14:9: error: expected identifier or '(' before 'return'
   14 |         return 0;
      |         ^~~~~~
/in/foo.c:15:1: error: expected identifier or '(' before '}' token
   15 | }
      | ^