关于strcmp这个函数标准时这样规定的：

int strcmp ( const char * str1, const char * str2 );

Compare two strings

Compares the C string str1 to the C string str2.
This function starts comparing the first character of each string. If they are equal to each other, it continues with the following pairs until the characters differ or until a terminating null-character is reached.

Parameters

str1 

C string to be compared. 

str2 

C string to be compared.

Return Value

Returns an integral value indicating the relationship between the strings:
A zero value indicates that both strings are equal.
A value greater than zero indicates that the first character that does not match has a greater value in str1 than in str2; And a value less than zero indicates the opposite.

在VC中strcmp("123","1234") 返回-1,而在TC中返回-52。

标准只是规定三个值：小于零，零，大于零。具体是什么值编译器自己定的，所以编程时候判断小于等于大于，不能判断是否等于1或者-1