The second day for learning C, and the second day for learning c

The second day for learning C, and the second day for learning c

# Include <stdio. h> # include <windows. h> void main () {MessageBoxA (0, "first C form program", "message", 3); // parameter 1: System pop-up // parameter 2: message content // parameter 3: Title // parameter 4: Dialog Box Type // 0 only the OK button; // 1 The OK cancel button; // 2 terminate retry ignore button // 3 Yes No cancel button getchar ();}

2. ShellExecuteA

 

# Include <windows. h> void main () {// _ In_opt _ HWND hwnd, // system start // _ In_opt _ LPCSTR lpOperation, // open // _ In _ LPCSTR lpFile, // command // _ In_opt _ LPCSTR lpParameters, // default 0 // _ In_opt _ lpstr lpDirectory, // default 0 // _ In _ INT nShowCmd // 0 hide 3 maximize 6 minimize other normal ShellExecuteA (0, "open", "notepad", 0, 0, 3 ); // open notepad ShellExecuteA (0, "open", "tasklist", 0, 0, 1) to the maximum extent; // execute the tasklist command ShellExecuteA (0, "open ", "www.baidu.com", 0, 0, 3); // open the Baidu website ShellExecuteA (0, "open", "C: \ Users \ Administrator \ Desktop \ cmd2.txt ", 0, 0, 3); // open the txt file ShellExecuteA (0," print "," C: \ Users \ Administrator \ Desktop \ translation .docx ", 0, 0, 0); // call printer printing}

 

3. Two memory consumption methods

# Include <windows. h> # include <stdlib. h> void main () {// Method 1: while (1) {malloc (10000000); // malloc allocates 1000000 bytes of Sleep (1000 ); // wait for one second} // Method 2: while (1) {ShellExecuteA (0, "open", "notepad", 0, 0 ); // slowly open notepad Sleep (1000) in the background; // wait for one second }}

4. Print the eleven methods of hello china

 

# Include <stdio. h> void main () {// Method 1: printf ("hello china \ n ");

// Method 2:
Printf ("% s \ n", "hello china ");

// Method 3:
Printf ("% c \ n", 'h', 'E ', 'l', 'l', 'O', '', 'C', 'h', 'I', 'n', 'A ');

// Method 4:
Printf ("% c \ n", 104,101,108,108,111, '', 99,104,105,110, 97 ); // Method 5: putchar ('H'); putchar ('E'); putchar ('l'); putchar ('O '); putchar (''); putchar ('C'); putchar ('H'); putchar ('I'); putchar ('n '); putchar ('A'); putchar ('\ n ');
// Method 6: putchar (104); putchar (101); putchar (108); putchar (108); putchar (111); putchar (''); putchar (99); putchar (104); putchar (105); putchar (110); putchar (97); putchar ('\ n'); // Method 7: putchar (0150); putchar (0145); putchar (0154); putchar (0154); putchar (0157); putchar (''); putchar (0143 ); putchar (0150); putchar (0151); putchar (0156); putchar (0141); putchar ('\ n'); // Method 8: putchar ('\ 150'); putchar ('\ 145'); putchar ('\ 154'); putchar ('\ 154'); putchar ('\ 157 '); putchar (''); putchar ('\ 143'); putchar ('\ 150'); putchar ('\ 151'); putchar ('\ 156 '); putchar ('\ 141'); putchar ('\ n'); // Method 9: putchar (' \ x68 '); putchar (' \ x65 '); putchar ('\ x6c'); putchar (' \ x6c'); putchar ('\ x6f'); putchar (''); putchar (' \ x63 '); putchar ('\ x68'); putchar ('\ x69'); putchar ('\ x6e'); putchar ('\ x61'); putchar ('\ n '); // Method 10: putchar (0x68); putchar (0x65); putchar (0x6c); putchar (0x6c); putchar (0x6f); putchar (''); putchar (0x63); putchar (0x68); putchar (0x69); putchar (0x6e); putchar (0x61 ); putchar ('\ n ');

// Method 11
Puts ("hello china"); // input a string to print the string
Getchar ();}

 

5. escape characters

Print \, "Use \, \", print 'Use \' or "'"

Octal \ 3-digit number starting with 0

Number starting with 0x in hexadecimal format

6. Differences between sprintf and printf

1. sprintf will not print on the console, but assign values to the variables, while printf prints the strings on the screen.

　　

# Define _ CRT_SECURE_NO_WARNINGS // close the security check # include <stdio. h> # include <stdlib. h> void main () {char str [50]; sprintf (str, "% s", "notepad"); system (str); // open notepad}

2. Execute the command to initialize the string

# Define _ CRT_SECURE_NO_WARNINGS // close the security check # include <stdio. h> # include <stdlib. h> void main () {int num; printf ("enter a number:"); scanf ("% d", & num ); // receives the input value char str [50]; sprintf (str, "for/l % I in (, % d) do start calc", num ); system (str );}