/in/foo.c: In function 'main':
/in/foo.c:55:5: error: expected declaration or statement at end of input
     return 0;
     ^
/in/foo.c:10:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s", str);   //输入ISBN号
     ^