C Function Daquan-remove less frequently used.

I. <Math. h>

1. abs () Absolute Value Function

2. Note that when gcc compiles a program with the math. h header file in unix/linux, we need gcc abc. c-lm => link-lm to indicate the math library.

3. floor () ceil () is an integer after (top) the current value. For example, 15.5 floor () => 15 ceil () => 16

4. div () is used to calculate the quotient and remainder of two integers; div_t div (int number, int denom); ====), not in math. h, but in stdlib. h ....

Typedef struct

{

Long int quot; // Operator

Long int rem; // Remainder

} Div_t;

5. fabs () calculates the absolute value of the floating point number;-123.5 = "123.5

6. srand () rand () radom () randomize () Random Number

7. sqrt () Square Root

8. pow pow10 power

9. modf modfl: split into integer and decimal parts

1. max min

2. fmod calculates the modulus of x/y: remainder.