foo.cc: In function 'int main()':
foo.cc:7:5: error: 'memset' was not declared in this scope
     memset(x,0, sizeof(x));
     ^~~~~~
foo.cc:7:5: note: suggested alternative: 'wmemset'
     memset(x,0, sizeof(x));
     ^~~~~~
     wmemset
foo.cc:8:12: warning: unused variable 'i' [-Wunused-variable]
     long n,i,top;
            ^

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