使用子字符串C ++获得奇怪的输出

Question

so I am having some odd problems with what seems like a very simple problem.

I have a vector:

vector(string) collectionOfLines;

This holds lines of text that I got from a .txt file. The contents of the text file are:

"4

Disk 0.2 0.00005

Mouse 0.4 0.00002

Keyboard 0.3 0.00004

Network 0.5 0.0001"

collectionOfLines[0] = "Disk 0.2 0.00005"

I am trying to separate this string into three different strings that are: "Disk", "0.2", and "0.00005" and then put these strings into a different vector:

vector(string) collectionOfCommands;

This is my loop for getting the substrings from the line string and putting them into the new vector.

string deviceName;
string interruptProbability;
string interruptTime;

for(int i = 1; i < collectionOfLines.size(); i++) { // i = 1 because I am ignoring the "4" in the txt file
    string currentLine = collectionOfLines[i];
    int index = 0;
    for(int j = 0; j < currentLine.length(); j++) {
        if(j == 0) {
            continue;
        } else if(deviceName.empty() && currentLine[j-1] == ' ') {
            deviceName = currentLine.substr(index, j-1);
            index = j;
        } else if (interruptProbability.empty() && currentLine[j-1] == ' ') {
            interruptProbability = currentLine.substr(index, j-1);
            index = j;
        } else if (!deviceName.empty() && !interruptProbability.empty()) {
            interruptTime = currentLine.substr(index, currentLine.length());
            break;
        } else {
            continue;
        }
    }
    collectionOfCommands.push_back(deviceName);
    collectionOfCommands.push_back(interruptProbability);
    collectionOfCommands.push_back(interruptTime);
}

When I run this I get no errors, but when I print the output of collectionOfCommands I get:

"Disk

0.2 0.00

0.00005

Disk

0.2 0.00

Mouse 0.4 0.00002

Disk 0.2 0.00

Keyboard 0.3 0.00004

Disk 0.2 0.00

Network 0.5 0.0001"

Obviously this output is completely wrong except for the very first output, "Disk."

Help would be much appreciated, thank you!!!!

Answer 1

This is a weird way of breaking up a string especially since you already know of a consistent format. Is there a paticular reason you are using substr()? Try using an input string stream instead.

    #include <sstream>
    #include <string>
    ...

    istringstream iss(currentLine);

    getline(iss, deviceName, ' ');
    getline(iss, interruptProbability, ' ');
    getline(iss, interruptTime);