Conversion on Initialization and assignment

Assigning a value to a type with a greater range usually poses no problem.
If shorter range or different type, maybe there are some problems.
assigned to a bool, zero will convert to false, and nonzero will convert to true.
When conversion, maybe loss precision(double -> float ) loss fragment(float -> i) or Undefine (int i = 666, then char c = i;) Detail example can be seen in my evernote bookmark.
int i, float f;
i+f // i will promoted to f and value keep the same.
i=f  // conversion,  1) fragment will be lost,
      // f= 3.99, i will be 3 (not rounding)
      //or maybe 2) If f is too big.  undefined behave

f = long long // will lost precision.
In C++, introduce a {}, It will not allow narrowing happen
int x = 66;
char c1 = {x}; //ok

int x = 666;
char c2 = {x}; // not allowed;