[Study Notes] [C Language] arithmetic operations, learning notes arithmetic operations

[Study Notes] [C Language] arithmetic operations, learning notes arithmetic operations

There are 34 operators in C language, including common addition, subtraction, multiplication, division, and so on.

1. addition operation +

In addition to addition, the addition operation can also represent the positive signs: + 5, + 90

2. subtraction-

The subtraction operation can also represent symbols-10 and-29.

3. Multiplication operation *

Note that the symbol is not x, *

4. division operation/

Note that the symbol is neither forward nor \,/

An integer is an integer except an integer. The value of 1/2 is 0, which is not 1/2

5. remainder operation %

What is remainder? The remainder after division of two integers

% Both sides can only be integers

Positive and negative are determined by the value on the left of %.

6. Notes

1> automatic type conversion

Int a = 10.6;

Int B = 10.5 + 1.7;

Automatically converts large data types to small ones, leading to loss of precision.

2> automatic type upgrade

Int B = 10.5 + 10;

Increase 10 on the right to the double type.

Double B = 1.0/2;

Solve the Division precision Problem

3> forced type conversion

Double a = (double) 1/2;

Double B = (double) (1/2 );

4> Operation Sequence

Expression

Combination (integration direction): 2 + 3 + 4

Priority: 5 + 4*8-3

 

Operator priority (from high to low)

Priority	Description	Operator
1	Brackets	(), []
2	Plus or minus sign	+ ,-
3	Auto-increment and auto-increment, not	++ ,--,!
4	Multiplication, division, and remainder	*,/, %
5	Addition and subtraction	+ ,-
6	Shift operation	<,>,>
7	Size relationship	>,>=, <, <=
8	Equality	= ,! =
9	Bitwise AND	&
10	Bitwise OR	^
11	By bit or	|
12	Logic and	&&
13	Logic or	|
14	Conditional operation	? :
15	Value assignment	=, + =,-=, * =,/=, % =
16	Bit value assignment	& =, | =, <=, >>=, >>>> =

If you want to change the operation sequence in a program, you can use ().

7. course code

1 # include <stdio. h> 2 3 int main () 4 {5/* 1. 6 int a = 10 + 1 + 2-3 + 5; 7 8 int B =-10; 9 10 int c = 10 * B; 11 12 int d = 10/2; 13 14 // remainder operation (modulo operation) 15 // % both sides are integers 16 // % the positive and negative result of the remainder result is only related to the value on the left of % 17 int e = 10%-3; 18 printf ("% d \ n", e); 19 */20 21/* 22 // automatic type conversion (double-> int) 23 int a = 10.8; 24 25 // forced type conversion (double-> int) 26 int B = (int) 10.5; 27 printf ("% d \ n", ); 28 */29 30 // automatic type increase (int-> double) 31 double c = 10.6 + 6; 32 33 double d = 1/3; 34 35 double e = (double) 3/2; 36 37 printf ("the value of e is % f \ n", e); 38 39 40 return 0; 41}

 

1 # include <stdio. h> 2/* 3: the user is prompted to enter the number of seconds of a time. For example, if the value is 500 in 500 seconds, the corresponding minutes and seconds are output, for example, 96546546 S is 8 minutes, 20 seconds, 4 */5 int main () 6 {7/* 8 // set the value of c to 9 int a = within 10; 10 11 int c = a % 10; 12 */13 14 // 1. prompt the user to enter the time 15 printf ("Please enter a time value (seconds): \ n"); 16 17 // 2. time of receiving user input 18 int time; 19 scanf ("% d", & time); 20 21 // 3. convert to the corresponding minute and second 22 int minute = time/60; // minute 23 int second = time % 60; // seconds 24 25 printf ("% d seconds = % d minutes % d seconds \ n", time, minute, second); 26 27 return 0; 28}