Convert float to std::string in C++
Unless you’re worried about performance, use string streams: If you’re okay with Boost, lexical_cast<> is a convenient alternative: Efficient alternatives are e.g. FastFormat or simply the C-style functions.
type-conversion
Using ssize_t vs int
There’s no guarantee in the POSIX standard that sizeof(int) >= sizeof(ssize_t), nor the other way around. Typically ssize_t is larger than int, but the safe and portable option in C99 is to use intmax_t instead for the argument and the return value. The only guarantees you have wrt. the relationship between int and ssize_t are: int can store values of at least the range [-2^15 … … Read more
How do I convert a string to a number in PHP?
You don’t typically need to do this, since PHP will coerce the type for you in most circumstances. For situations where you do want to explicitly convert the type, cast it:
Converting characters to integers in Java
The java.lang.Character.getNumericValue(char ch) returns the int value that the specified Unicode character represents. For example, the character ‘\u216C’ (the roman numeral fifty) will return an int with a value of 50. The letters A-Z in their uppercase (‘\u0041’ through ‘\u005A’), lowercase (‘\u0061’ through ‘\u007A’), and full width variant (‘\uFF21’ through ‘\uFF3A’ and ‘\uFF41’ through ‘\uFF5A’) forms have numeric values from 10 through 35. This is … Read more
SQL error “ORA-01722: invalid number”
A very easy one for someone, The following insert is giving me the ORA-01722: invalid number why?
How can I convert a char to int in Java? [duplicate]
The ASCII table is arranged so that the value of the character ‘9’ is nine greater than the value of ‘0’; the value of the character ‘8’ is eight greater than the value of ‘0’; and so on. So you can get the int value of a decimal digit char by subtracting ‘0’.
Convert String to double in Java
You can use Double.parseDouble() to convert a String to a double: For your case it looks like you want:
How to convert a char to a String?
You can use Character.toString(char). Note that this method simply returns a call to String.valueOf(char), which also works. As others have noted, string concatenation works as a shortcut as well: But this compiles down to: which is less efficient because the StringBuilder is backed by a char[] (over-allocated by StringBuilder() to 16), only for that array to be defensively copied by the resulting String. String.valueOf(char) “gets in … Read more