把某个特定的字符转换为大写

#include<iostream>

#include<fstream>

#include<String>

using namespace std;



int main()

{

    ifstream fin;

    ofstream fout;

    string str1,str2;

    char ch;

    int length;

    cout<<"Input the infilename:"<<endl;

    cin>>str1;

    fin.open(str1.c_str(),ifstream::binary|ifstream::in);

    fin.seekg(0,ifstream::end);

    length=fin.tellg();

    fin.seekg(0,ifstream::beg);

    cout<<length<<endl;

    char* in_array=new char[length];

    fin.read(in_array,length);

    cout<<"Input the char to change case:"<<endl;

    cin>>ch;

    for(int i=0;i<length;i++)

    {

            if(in_array[i]==ch)

            in_array[i]-=32;

            cout<<in_array[i]<<" ";

    }

    cout<<"Input the outfilename:"<<endl;

    cin>>str2;

    fout.open(str2.c_str(),ofstream::binary|ofstream::out);

    fout.write((char*)in_array,length);

    fin.close();

    fout.close();

    delete[] in_array;

    return 0;




}