[英]How do I skip reading a line in a file in C++?
The file contains the following data: 该文件包含以下数据:
#10000000 AAA 22.145 21.676 21.588
10 TTT 22.145 21.676 21.588
1 ACC 22.145 21.676 21.588
I tried to skip lines starting with "#" using the following code: 我尝试使用以下代码跳过以“#”开头的行:
#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
using namespace std;
int main() {
while( getline("myfile.txt", qlline)) {
stringstream sq(qlline);
int tableEntry;
sq >> tableEntry;
if (tableEntry.find("#") != tableEntry.npos) {
continue;
}
int data = tableEntry;
}
}
But for some reason it gives this error: 但由于某种原因,它给出了这个错误:
Mycode.cc:13: error: request for member 'find' in 'tableEntry', which is of non-class type 'int' Mycode.cc:13:错误:请求'tableEntry'中的成员'find',这是非类型'int'
Is this more like what you want? 这更像你想要的吗?
#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <algorithm>
using namespace std;
int main()
{
fstream fin("myfile.txt");
string line;
while(getline(fin, line))
{
//the following line trims white space from the beginning of the string
line.erase(line.begin(), find_if(line.begin(), line.end(), not1(ptr_fun<int, int>(isspace))));
if(line[0] == '#') continue;
int data;
stringstream(line) >> data;
cout << "Data: " << data << endl;
}
return 0;
}
You try to extract an integer from the line, and then try to find a "#" in the integer. 您尝试从该行中提取整数,然后尝试在整数中找到“#”。 This doesn't make sense, and the compiler complains that there is no find
method for integers. 这没有意义,编译器抱怨没有整数的find
方法。
You probably should check the "#" directly on the read line at the beginning of the loop. 您可能应该在循环开始时直接在读取行上检查“#”。 Besides that you need to declare qlline
and actually open the file somewhere and not just pass a string with it's name to getline
. 除此之外,您需要声明qlline
并实际在某处打开文件,而不只是将带有名称的字符串传递给getline
。 Basically like this: 基本上是这样的:
ifstream myfile("myfile.txt");
string qlline;
while (getline(myfile, qlline)) {
if (qlline.find("#") == 0) {
continue;
}
...
}
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