Dark Horse Programmer-C language Notes

Android training, Java training, iOS training,. NET training look forward to communicating with you!

A. C Language study notes

Thank the Dark Horse to provide a platform, thank teachers!

　　My first C language program:

The first step in learning a language is to first export "Hello World", which originated in 1972, and Bell Labs researcher Brian Kernighan is writing "B language Tutorials and guidance (Tutorial Introduction to the Language b First Use (program), this is the earliest known record of the use of Hello and world in computer works. Later, in 1978, he and Dennis Ritchie co-authored the C-Language Bible "The C programming Language", the use of "Hello, world" sentence, as the opening of the first program. In this program, the output of "Hello, world" is all lowercase, no exclamation point, a comma after a space. Although the original format was rarely passed down after that, it was customary to greet the world with the greetings and personal feelings could be a tribute.　　

1 #include <stdio.h>23int main (intconstChar * argv []) {4  5      printf ("HelloWorld");   Enter Hello World67      return0;     8 }

　　

　　in the C language, The function declaration is in the Header.h file, and the implementation of the function is in the ***.c file.

1. You can import the ". h" header file when using the function, and if you import the ". C" File There will be a duplicate function error

　　(Note: You can use the angle brackets "<stdio.h>" and the double quotation mark " stdio.h"when importing the header file of the system itself, but to import a header file that is not the system itself, double quotation marks are used, for example:"MyTest.h" )

　　

　　2. Condition Judgment, Example: if (a = = 3) It is best to write if (3 = = a), if you omit a "=" in the code, then the compiler will prompt, and the previous type of compilation passed,

The result assigns a value of 3 to a.

　　

3. Array, array is a constant, can only be initialized when the array is defined, otherwise you cannot assign a value to the array at a later stage.

①: The address of the array is the byte address of the first element in the array, for example:

1 CharA [] = {'I','T' };2 /*defines an array of type char, named A, that holds two elements in the array*/3 4 Address:5 1. printf"%d", &a[0]);//output address is 16382126 7 2. printf ("%d", &a);//output address is 1638212

the difference between 4.printf and puts is the same as the output function:

①printf can output multiple elements at the same time, separated by commas, but the put can only output a single element at a time

②printf output is required to add "\ n" to wrap, and puts to wrap.

int main (int argc,const char * argv[]) {    printf ("Black Horse, Hello! \ n ");    Puts ("Black Horse, Hello!" ");   }
/* Output is changed the line of "Dark Horse, Hello!" "*/

Thank the Dark Horse to provide a platform, I hope that they can make unremitting efforts!

Dark Horse Programmer-C language Notes