foo.cc: In function 'int main()':
foo.cc:54:5: error: expected ';' before 'for'
     for(int i=0;i<n;i++){
     ^~~
foo.cc:54:17: error: 'i' was not declared in this scope
     for(int i=0;i<n;i++){
                 ^
foo.cc:53:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n)
     ~~~~~^~~~~~~~~

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