C++ |计算文件中两个特定点之间的行数[关闭]

Question

我最近刚开始使用 c++，很想知道如何计算文件中特定点之间的行数。我已经可以成功找到我想开始计数的第一个点，但我不知道如何进一步计算。

这是我目前得到的：

ifstream fin;
string line;

char* search = "Key:";
char* search2 = "Color:";

// Open the file.
fin.open(filename);

// Check if it was successful in opening the file.
if (fin.fail() == true)
{
    return false;
}

// Read from the file and continue to read until the end of the file is reached.
while (getline(fin, line)) {

    if (line.find(search, 0) != string::npos) {
        //Start counting line ??
    }
}

非常感谢您的帮助。

Answer 1

首先你需要一个变量来存储计数，然后你还需要一个变量来确定你当前是否在计数：

int count = 0;
bool counting = false;

while(...) {
  if(...)
    counting = true;

  if(...)
    counting = false;

  if(counting)
    ++count
}

Answer 2

使用您的代码，例如：

unsigned int count_lines=0;
unsigned int ignore_lines=0;

// Read from the file and continue to read until the end of the file is reached.
while (getline(fin, line)) {
    count_lines++;
    if (line.find(search, 0) != string::npos) {
        ignore_lines = count_lines;
    }
    if (line.find(search2, 0) != string::npos) {
        // The number of rows is count_lines - ignore_lines
    }
}