foo.c: In function 'main':
foo.c:5:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&x);
     ^~~~~~~~~~~~~~
foo.c:8:16: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
             sum+=i;
             ~~~^~~

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