[英]Extracting number from file C++
在我的程序中,我想從一行中提取一個數字(代表以秒為單位的停止時間),從中我減少我從下一行提取的另一個數字(代表以秒為單位的開始時間),然后寫入結果在結果文件中。
我有以下代碼:
# include <iostream>
# include <fstream>
# include <string>
# include <streambuf>
using namespace std;
int main ()
{
ifstream f;
ofstream g;
f.open("Processes.txt");
g.open("Results.txt");
long last_el,top_nr=0,stop_nr=0,start_nr=0,stop_time_count=1,start_time_count=1,inter_count=0,global_count,final_result_count=1;
long pow_start_nr=7,pow_stop_nr=7,stop_time[1000],start_time[1000],final_result[1000];
string text_el;
stringstream strStream;
strStream << f.rdbuf();
string str = strStream.str();
last_el=text_el.size();
// while(text.el)
// {
for(global_count=0;global_count<last_el;global_count++)
{
if(text_el[global_count]=='*')
{
inter_count=global_count+1;
for(global_count=inter_count;global_count<=inter_count+7;global_count++)
{
start_nr=start_nr+(10^pow_start_nr)*text_el[global_count];
pow_start_nr--;
}
start_time[start_time_count]=start_nr;
start_time_count++;
global_count=inter_count+8;
}
}
for(global_count=0;global_count<last_el;global_count++)
{
if(text_el[global_count]=='#')
{
inter_count=global_count+1;
for(global_count=inter_count;global_count<=inter_count+7;global_count++)
{
stop_nr=stop_nr+(10^pow_stop_nr)*text_el[global_count];
pow_stop_nr--;
}
stop_time[stop_time_count]=stop_nr;
stop_time_count++;
global_count=inter_count+8;
}
}
// }
for(final_result_count=1;final_result_count<2;final_result_count++)
{
final_result[final_result_count]=stop_time[stop_time_count]-start_time[start_time_count];
stop_time_count++;
start_time_count++;
g<<"The time for process number"<<" "<< final_result_count <<" "<<"is"<<" "<< final_result[final_result_count] <<endl<<endl;
}
f.close();
g.close();
}
在我的退出文件中,它只寫為 0。
我不知道為什么會發生這種情況。 我認為從文件中讀取的文本有問題。 在那里,帶有“ a ”向量。 我是 C++ 的菜鳥。
樂:
# include <iostream>
# include <fstream>
# include <string>
# include <sstream>
# include <streambuf>
using namespace std;
int main ()
{
ifstream f;
ofstream g;
f.open("Processes.txt");
g.open("Results.txt");
long startTime[1000],endTime[1000];
string nextLine;
int lineNum = 1;
while (getline(f, nextLine))
{
getline(f, nextLine);
startTime[lineNum] = stoi(nextLine.substr(14,8));
g<<startTime[lineNum]<<"xxxx";
endTime[lineNum+1] = stoi(nextLine.substr(27,8));
g<<endTime[lineNum]<<"xxxx";
getline(f, nextLine);
getline(f, nextLine);
getline(f, nextLine);
lineNum=lineNum+3;
}
f.close();
g.close();
}
輸入文件:
------------------------------------------------------------------------------
started at: *00000005 Number: 1
completed at: #00000065 Number: 1
------------------------------------------------------------------------------
------------------------------------------------------------------------------
started at: *00000000 Number: 2
completed at: #00000100 Number: 2
------------------------------------------------------------------------------
------------------------------------------------------------------------------
started at: *09999999 Number: 3
completed at: #10000000 Number: 3
正如我相信您最近的評論所述,您已經找到了處理此問題的最佳方法。 您想讀取每一行並解析字符串。 類似如下:
std::string nextLine;
int lineNum = 0;
while (std::getline(f, nextLine)) {
startTime[lineNum] = std::stol(nextLine.substr(14,8));
endTime[lineNum] = std::stol(nextLine.substr(50,8));
lineNum++;
}
公平警告:我實際上並沒有仔細計算這些偏移量,所以我可能會偏離一些。 此外,您還必須考慮那些只有破折號的“空白”線。 但我會讓你去打掃房間。
希望這能讓你走上正確的道路!
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