标准的C++ string类里有没有把string变为全大写的函数

luddy2

找了半天没有找到，怀疑是不是没有啊，还是要自己写的？ :ask

younker

确实没有不过可以使用
transform(s.begin(), s.end(), s.begin(), toupper);

algorithm 文件中的一个算法。

luddy2

哦，那换一个问题，我能不能把一个文件中的字符按照大写字母输出给一个string对象？
我试了一下
    string token;
    ifstream fin("Test_0.sp",ios::in);
    fin.setf(ios::uppercase);
    while (fin>>token) {
        cout<<token<<endl;
    }
    fin.close();
    return 0;

好像不行

ice226

toupper-Convert a character to uppercase

Synopsis

        #include <ctype.h>

        cc = toupper(c);

        int cc;  /* converted character */
        int c;         /* character to convert */

Description

        The toupper function is the reverse of the  tolower  function.

        You can use either characters or integers as arguments, but the
        macro is defined only over the integer range from -1 to 255.  The
        function, however, will return a result for values above 255, but
        the results are not necessarily correct and cannot be relied upon.
        The reason -1 is included as a valid argument is to avoid a
        nonsensical result if you feed the EOF value to one of the macros
        or functions.  EOF can be returned by the  getchar  function and
        other I/O functions, and if you pass it to any of the character
        test functions, the return value will be 0.

        If you include the file ctype.h as shown above, this function is
        actually defined as a macro and produces inline code to perform
        the conversion.  Without the ctype.h file, it is an actual
        function resolved in the standard library.  If you want to use the
        function version but must include the file ctype.h for some other
        reason, use an #undef statement to undefine the macros after
        including the ctype.h file.

            #undef toupper


Example

        /*
         * The following program echoes each input
         * line in upper case.
         */
        #include <stdio.h>
        #include <ctype.h>

        void main(void)
        {
            char b[256],*p;

            while(gets(b) != NULL)
            {
                for (p = b; *p != '0'; p++)
                {
                    *p = toupper(*p);
                }
                puts(b);
            }
        }