#include<iostream>
#include<fstream>
#include<string>

using namespace std;

int main()
{
    char filename[50];
    char output_file_name[50];
    cout<<"input the file name:";
    cin>>filename;

    ifstream in(filename);
    if(in.fail())
    {
        exit(1);
    }

    cout<<"input the output file name:";
    cin>>output_file_name;

    ofstream out(output_file_name);

    string s,line;
    while(getline(in,line))
    {
        s+=line+"\n";
    }

    for(int i=0; i<s.length(); i++)
    {
        if(s[i]>='a' && s[i]<='z')
        {
            s[i]=s[i]-32;
        }
    }
    out<<s;
    return 0;
}///:p

总觉的还有更好的方法，不要把整个文件的内容读入一个字符串

还有， doc文档怎么读不进去，输出乱码，怎么读doc,

回复者给于精神和加分支持^_^