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How to pass variable in C   Sprintf 2nd(format) argument?
string format = "what is your %s";
new_string = sprintf(buffer, format, name);

string format = "what is your %s";
int total = sprintf(buffer, format.c_str(), name);

std::ostringstream os;
os << "what is your " << name;
std::string new_string = os.str();

char buffer[100];
string format = "what is your %s";
sprintf(buffer, format.c_str(), name.c_str());
string new_string(buffer);

stringstream buf;
buf << "what is your " << name;
string new_string = buf.str();

int len = sprintf(buffer, "what is your%s", name);
std::string new_string(buffer, len);