foo.cc:1:9: error: #include expects "FILENAME" or <FILENAME>
    1 | #include
      |         ^
foo.cc:5:1: error: 'ifstream' does not name a type
    5 | ifstream fin("a.in");
      | ^~~~~~~~
foo.cc:7:1: error: 'ofstream' does not name a type
    7 | ofstream fout("a.out");
      | ^~~~~~~~
foo.cc: In function 'int main()':
foo.cc:15:1: error: 'fin' was not declared in this scope
   15 | fin>>m;
      | ^~~
foo.cc:19:10: error: invalid operands of types 'int' and 'int [1001]' to binary 'operator-'
   19 | b[i]=a[i]-a;
      |      ~~~~^~
      |         | |
      |         | int [1001]
      |         int
foo.cc:19:12: error: expected ')' before ';' token
   19 | b[i]=a[i]-a;
      |            ^
      |            )
foo.cc:17:4: note: to match this '('
   17 | for(i=1;i>a[i];
      |    ^
foo.cc:13:7: warning: unused variable 'j' [-Wunused-variable]
   13 | int i,j,m,a[1001]={0},b[1001]={0};
      |       ^
foo.cc: At global scope:
foo.cc:23:1: error: 'j' does not name a type
   23 | j=b[m]-b[m-1]+b[m];
      | ^
foo.cc:25:1: error: 'fout' does not name a type
   25 | fout
      | ^~~~

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