#Linux中的GCC规划# Some useful small function C code

1. Enter and identify the up, down, left, and right on the keyboard

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

//分配内存的大小
#define     SIZE    10
//定义按键们的宏
#define     ESC     "\033"
#define     UP      "\033[A"
#define     DOWN    "\033[B"
#define     LEFT    "\033[D"
#define     RIGHT   "\033[C"

int main()
{
    char *get = (char*)malloc(SIZE);

    for ( ; ; ) 
    {   
        fgets(get, SIZE, stdin);
        /*    用fgets()函数从stdin中读取字符串时，会自动在字符串末尾追加"\n"，这里将末尾字符改为"\0"    */
        get[strlen(get) - 1] = '\0';

        if (!strcmp(get, ESC))
            printf("This is \"ESC\" button!\n");
        if (!strcmp(get, UP))
            printf("This is \"UP\" button!\n");
        if (!strcmp(get, DOWN))
            printf("This is \"DOWN\" button!\n");
        if (!strcmp(get, LEFT))
            printf("This is \"LEFT\" button!\n");
        if (!strcmp(get, RIGHT))
            printf("This is \"RIGHT\" button!\n");
    }   

    return 0;
}

Operation result: Each time you press an arrow key, you need to press Enter again (used to refresh the cache).

kshine@kshine-virtual-machine:~/桌面/GCC$ gcc udlr1.c  -o main -Wall
kshine@kshine-virtual-machine:~/桌面/GCC$ ./main
^[[A
This is "UP" button!
^[[D
This is "LEFT" button!
^[[B
This is "DOWN" button!
^[[C
This is "RIGHT" button!

2. For the above test code, we can introduce system("stty -icanon"); as shown in the following code

#include <stdio.h>
#include <stdlib.h>
int main()
{
        char ch;
        system("stty -icanon");//关闭缓冲区，输入字符无需回车直接接受
        ch = getchar();
        if(ch == 'a')
                printf("OK\n");
        return 0;
}

3. printf(), highlight

#include"stdio.h"
int main()
{
	printf("\033[40;39m  底色40黑色，字色39无无  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[41;38m  底色41深红，字色38无无  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[42;37m  底色42绿色，字色37白色  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[43;36m  底色43黄色，字色36深绿  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[44;35m  底色44蓝色，字色35紫色  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[45;34m  底色45紫色，字色34蓝色  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[46;33m  底色46深绿，字色33黄色  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[47;32m  底色47白色，字色32绿色  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[48;31m  底色48无无，字色31红色  \033[0m\n");//\033[;m  ……  \033[0m
	printf("\033[49;30m  底色49无无，字色30黑色  \033[0m\n");//\033[;m  ……  \033[0m
	return 0;
}