Learn from Yin Cheng and C + + 008

Comma operator
Lowest priority level
The value of the comma operator is the last value
int a= (UP);
Execution result is 2
The comma operator is executed for each statement, and the direction of execution is left to right

Trinocular operator
Expression 1-expression 2: Expression 3

There are only 0 and 0 differences in C language.

The trinocular operator takes the maximum value, the minimum value

Data mining

Relational operators are left-to-right in the direction of operation
If the 3>2>1 judge the result is 0

Same constant string that stores the same address

logical operators
Logical "and" Operators &&
Logical "or" operator | |
Logical "not" operator

"and" operator short-circuit effect, a condition does not conform to continue to carry out in the future
"or" operator short-circuit effect, a condition conforming to the following will not be performed

CGI output information on the server

#include <stdio.h>
#include <stdlib.h>

void Main ()
{
printf ("content-type:text/html\n\n"); Declaring the HTML language
printf ("Hello");

}

Input and output of data
Printf
Output to file, command line, Web page

sprintf input to String

printf ("\n%10d", 10); Width is 10, default right is aligned,-left alignment right blank

. N Intercept strings and decimals, only from the left

32-bit%d and%ld int and long equivalents

Char str[100]= "Calc"; String

#include <stdio.h>
#include <string.h>

void Main ()
{
Char str[10] = "task";
Char newstr[10] = "list123";
Char strall[100] = {0};
sprintf (Strall, "%s%.4s", str, NEWSTR); string addition
System (Strall);
System ("pause");

}

void Main ()
{
Char str[10] = "task";
Char newstr[10] = "123list123";
Char strall[100] = {0};
sprintf (Strall, "%s%.4s", str, newstr+3); Use the move of the character address to crop to the left part of the string
System (Strall);
System ("pause");

}

%.10f. 10 decimal points reserved 10 digits

Index
E format character

%e Index output

%g automatically chooses to output real numbers in F or e format, depending on the size of the values, and automatically chooses a smaller width

%HD, short integer, 16-bit storage, 2^16-1,short range
%hu

%lu, long, 32-bit system with%lu,%ld equivalent to%u,%d
%ld

Store ID number, mobile number, long long%llu,%lld

%o% #o marked octal when the output of the # number is added

General octal, Hex plus #

%d,%o,%u cannot be capitalized
Except for X, E, and G, all other lowercase letters
Letter output can be case-%o exception

printf does not complete data type conversions and requires exact matching
\ escape Character

%.*f * To change the decimal position

Learn from Yin Cheng and C + + 008