Question

I have a fixed length character array I want to assign to a string. The problem comes if the character array is full, the assign fails. I thought of using the assign where you can supply n however that ignores \0s. For example:

std::string str;
char test1[4] = {'T', 'e', 's', 't'};
str.assign(test1);    // BAD "Test2" (or some random extra characters)
str.assign(test1, 4); // GOOD "Test"
size_t len = strlen(test1); // BAD 5

char test2[4] = {'T', 'e', '\0', 't'};
str.assign(test2);    // GOOD "Te"
str.assign(test2, 4); // BAD "Tet"
size_t len = strlen(test2); // GOOD 2

How can I assign a fixed length character array to a string correctly for both cases?

Answer 1

Use the “pair of iterators” form of assign.

str.assign(test1, std::find(test1, test1 + 4, '\0'));