CODEWITHSUNDEEP
c++printf
oops
oops

Reputation: 93

The usage of snprintf

Isn't it possible? When I remove d[%s], it was okay. Would you explain the reason?

std::string toString() const {
  char buf[1024];
  int a, b, c;
  std::string d;
  snprintf(buf, 1024, "a[%d] b[%d]" "c[%d] d[%s]", a, b, c, d);
  return buf;
}

Upvotes: 1

Views: 1391

Answers (1)

Holt
Holt

Reputation: 37616

snprintf does not work with std::string. The %s modifier is specified as follow:

The argument must be a pointer to the initial element of an array of characters. [...]

You need to pass a null-terminated array of characters. Fortunately, you can use c_str from std::string to obtain such pointer.

Just change your code to:

snprintf(buf, 1024, "a[%d] b[%d]" "c[%d] d[%s]", a, b, c, d.c_str());

Upvotes: 2

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