foo.cc: In function 'int main()':
foo.cc:8:15: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
    8 |  for(int i=0;i<strlen(xm);i++)
      |              ~^~~~~~~~~~~
foo.cc:9:3: error: 'sun' was not declared in this scope; did you mean 'sum'?
    9 |   sun+=(xm[i])
      |   ^~~
      |   sum
foo.cc:7:6: warning: unused variable 'sum' [-Wunused-variable]
    7 |  int sum=0;
      |      ^~~

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