foo.c: In function 'main':
foo.c:17:16: warning: too many arguments for format [-Wformat-extra-args]
         printf("Yes!\n",a);
                ^~~~~~~~
foo.c:19:16: warning: too many arguments for format [-Wformat-extra-args]
         printf("No!\n",a);
                ^~~~~~~
foo.c:8:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s",a);
     ^~~~~~~~~~~~~

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