问用fstream在最后一行上写

EN

#include <iostream>
#include <fstream>
#include <cstring>
Using namespace std;
int main()
{

fstream file("C:\\Users\\amir hossein\\Desktop\\Temp1\\test1.txt");

char *sub; sub = new char[20]; sub = "amir";
char *replace1; replace1 = new char[20]; replace1 = "reza";
char *buffer; buffer = new char[100];


int i, temp; streampos flag;
int c=0,mark;
bool flagforwrite=0;


if (file.is_open()){
    while (!file.eof()) {
        flag = file.tellg();
        file.getline(buffer, 100);    //We'll Search Sub inside of Buffer, if true, we'll replace it with Replace string
        flagforwrite=0;
        for (i=0;buffer[i];i++){
            mark=i; c=0;
            while (sub[c] && sub[c]== buffer[mark]){
                c++; mark++;
            }

            if (!sub[c]){   //Make Changes in The Line
                for (int j=i,count=0;count<strlen(replace1);j++,count++) buffer[j] = replace1[count]; //until here, we've replace1d the sub
                flagforwrite=1;
            }

        }

        if (flagforwrite){   //Write The line ( After Whole Changes In line have been made!!
                file.seekp(flag);
                file << buffer << "\n";   // ENDL here IS SUPER IMPORTANT!! IF you don't put it, I'll mess it up
                if(file.bad()) cout << "Error\n";
        }
    }
}

else cout << "Error!!\n";
file.close();  
delete[] sub;
delete[] replace1;
delete[] buffer;


return 0;
}

if (flagforwrite){ 
                    file.seekp(flag);
                    file << buffer << "\n";
                    if(file.bad()) cout << "Error\n";
            }