void replace(string& orignStr, const string& oldStr, const string& newStr) {
size_t pos = 0;
string::size_type newStrLen = newStr.length();
string::size_type oldStrLen = oldStr.length();
while (1) {
pos = orignStr.find(oldStr, pos);
if (string::npos == pos)
break;
orignStr.replace(pos, oldStrLen, newStr);
pos += newStrLen;
}
}