c_str（）似乎从C ++字符串类转换时消除了一些整数

Question

I am having difficulty converting a string I am reading from a file into an integer.

The output of my code below is:

Line Raw: 118
Line C:
Elem: 0

Line Raw: 121
Line C:
Elem: 0

Line Raw: 32
Line C: 32
Elem: 32

Any idea why converting to c_string seems to eliminate some integers?

The actual code that is causing this is below:

vector<int> compressed;
string encodedLine;
while (getline(inputFile, encodedLine)) {
    cout << "Line Raw: " << encodedLine << endl;
    cout << "Line C: " << encodedLine.c_str() << endl;
    int elem = atoi(encodedLine.c_str());
    cout << "Elem: " << elem << endl;
    compressed.push_back(elem);
}

The dump of the input file:

118
121
32

UPDATE: Thanks for all the quick answers! The problem was indeed the NULL character in the file. I noticed that the string 118 was showing as length 4. After doing the HexDump, I saw "00 31 31 38" and that confirmed this. Thanks!

Any suggestions for how to write to the file (which I control in another class in the program) without prepending NULL?

Answer 1

The problem is not in the standard library (what a surprise) nor in this piece of code (a somewhat smaller surprise). It works perfectly:

Answer 2

I suspect that your input file has null characters in it.

std:string has no problem holding a null character, but the C string functions treat it as the end of a string, of course.