c++ - 如何用实际值替换转义符号？

Question

我有一个像escape new lines\n这样的字符串。打印时，它不会用新行替换\n，而只是打印escape new lines\n。我正在遍历这个std::string，我想用它的实际值替换\n:

bool seenSlash = false;
for (int index = 0; index < text.length(); ++index) {
    if (text[index] == '\\') {
        seenSlash = true;
        continue;
    }
    if (seenSlash) {
        // what to do here?
        seenSlash = false;
    }
}

不只是 \n，我想支持所有这些转义符号。我该怎么做？

Answer 1

您可以做的是switch语句或使用常量std::map<char,char>:

if (seenSlash) {
    bool replace = false;
    switch(text[index]) {
    case 'n':
        replace = true;
        text[index-1] = '\n';
        break;
    case 't':
        replace = true;
        text[index-1] = '\t';
        break;
    // ... etc.
    }
    if(replace) {
        text.erase(text.begin() + index); // erase the cuurent char, the
                                          // backslash char was replaced
        --index; // adapt the index for the next iteration
    }
    seenSlash = false;
}

const std::map<char,char> escaped_chars = {
    { 'n', '\n' } ,
    { 't', '\t' } ,
    { 'a', '\a' } ,
    // ... etc.
};

if (seenSlash) {
    bool replace = escaped_chars.find(text[i]) != escaped_chars.end();
    if(replace) {
        text[index - 1] = escaped_chars[text[i]];
        text.erase(text.begin() + index); // erase the cuurent char, the
                                          // backslash char was replaced
        --index; // adapt the index for the next iteration
    }
    seenSlash = false;
}