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char *npos

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#include<stdio.h>
#include <string.h>
int main()
{
char command = "N7589iojf";
//gets(command);
char *npos = (*command == ‘N’)?command:NULL,
apos = strchr(command,’’);

printf("%c\n",*command);
printf("%s\n",apos);
printf("%s",npos);

}

local const

int main(int argc, const char * argv[]) {
const int a = 10;
int *p = (int *)&a;
printf("%p—%p—%p \n", &a, p, &p);
*p = 20;
printf("%p—%p—%p \n", &a, p, &p);
printf("%d–%d \n", a, *p);

// 0x7ffeefbff5fc—0x7ffeefbff5fc—0x7ffeefbff5f0
// 0x7ffeefbff5fc—0x7ffeefbff5fc—0x7ffeefbff5f0
// 10–20

return 0;

}

local static

#include <stdio.h>
void staic_fun(void)
{
int i = 0;
static int j;
i++;
j++;
printf("%d\t%d\t",i,j);

}
int main()
{
int cycle;
for(cycle=0;cycle<100;cycle++)
{
staic_fun();

}

}

looktable

#include <stdio.h>
const unsigned short speed_lookuptable_fast[256][2] = {
{ 62500, 55556}, { 6944, 3268}, { 3676, 1176}, { 2500, 607}, { 1893, 369}, { 1524, 249}, { 1275, 179}, { 1096, 135},
{ 961, 105}, { 856, 85}, { 771, 69}, { 702, 58}, { 644, 49}, { 595, 42}, { 553, 37}, { 516, 32},
{ 484, 28}, { 456, 25}, { 431, 23}, { 408, 20}, { 388, 19}, { 369, 16}, { 353, 16}, { 337, 14},
{ 323, 13}, { 310, 11}, { 299, 11}, { 288, 11}, { 277, 9}, { 268, 9}, { 259, 8}, { 251, 8},
{ 243, 8}, { 235, 7}, { 228, 6}, { 222, 6}, { 216, 6}, { 210, 6}, { 204, 5}, { 199, 5},
{ 194, 5}, { 189, 4}, { 185, 4}, { 181, 4}, { 177, 4}, { 173, 4}, { 169, 4}, { 165, 3},
{ 162, 3}, { 159, 4}, { 155, 3}, { 152, 3}, { 149, 2}, { 147, 3}, { 144, 3}, { 141, 2},
{ 139, 3}, { 136, 2}, { 134, 2}, { 132, 3}, { 129, 2}, { 127, 2}, { 125, 2}, { 123, 2},
{ 121, 2}, { 119, 1}, { 118, 2}, { 116, 2}, { 114, 1}, { 113, 2}, { 111, 2}, { 109, 1},
{ 108, 2}, { 106, 1}, { 105, 2}, { 103, 1}, { 102, 1}, { 101, 1}, { 100, 2}, { 98, 1},
{ 97, 1}, { 96, 1}, { 95, 2}, { 93, 1}, { 92, 1}, { 91, 1}, { 90, 1}, { 89, 1},
{ 88, 1}, { 87, 1}, { 86, 1}, { 85, 1}, { 84, 1}, { 83, 0}, { 83, 1}, { 82, 1},
{ 81, 1}, { 80, 1}, { 79, 1}, { 78, 0}, { 78, 1}, { 77, 1}, { 76, 1}, { 75, 0},
{ 75, 1}, { 74, 1}, { 73, 1}, { 72, 0}, { 72, 1}, { 71, 1}, { 70, 0}, { 70, 1},
{ 69, 0}, { 69, 1}, { 68, 1}, { 67, 0}, { 67, 1}, { 66, 0}, { 66, 1}, { 65, 0},
{ 65, 1}, { 64, 1}, { 63, 0}, { 63, 1}, { 62, 0}, { 62, 1}, { 61, 0}, { 61, 1},
{ 60, 0}, { 60, 0}, { 60, 1}, { 59, 0}, { 59, 1}, { 58, 0}, { 58, 1}, { 57, 0},
{ 57, 1}, { 56, 0}, { 56, 0}, { 56, 1}, { 55, 0}, { 55, 1}, { 54, 0}, { 54, 0},
{ 54, 1}, { 53, 0}, { 53, 0}, { 53, 1}, { 52, 0}, { 52, 0}, { 52, 1}, { 51, 0},
{ 51, 0}, { 51, 1}, { 50, 0}, { 50, 0}, { 50, 1}, { 49, 0}, { 49, 0}, { 49, 1},
{ 48, 0}, { 48, 0}, { 48, 1}, { 47, 0}, { 47, 0}, { 47, 0}, { 47, 1}, { 46, 0},
{ 46, 0}, { 46, 1}, { 45, 0}, { 45, 0}, { 45, 0}, { 45, 1}, { 44, 0}, { 44, 0},
{ 44, 0}, { 44, 1}, { 43, 0}, { 43, 0}, { 43, 0}, { 43, 1}, { 42, 0}, { 42, 0},
{ 42, 0}, { 42, 1}, { 41, 0}, { 41, 0}, { 41, 0}, { 41, 0}, { 41, 1}, { 40, 0},
{ 40, 0}, { 40, 0}, { 40, 0}, { 40, 1}, { 39, 0}, { 39, 0}, { 39, 0}, { 39, 0},
{ 39, 1}, { 38, 0}, { 38, 0}, { 38, 0}, { 38, 0}, { 38, 1}, { 37, 0}, { 37, 0},
{ 37, 0}, { 37, 0}, { 37, 0}, { 37, 1}, { 36, 0}, { 36, 0}, { 36, 0}, { 36, 0},
{ 36, 1}, { 35, 0}, { 35, 0}, { 35, 0}, { 35, 0}, { 35, 0}, { 35, 0}, { 35, 1},
{ 34, 0}, { 34, 0}, { 34, 0}, { 34, 0}, { 34, 0}, { 34, 1}, { 33, 0}, { 33, 0},
{ 33, 0}, { 33, 0}, { 33, 0}, { 33, 0}, { 33, 1}, { 32, 0}, { 32, 0}, { 32, 0},
{ 32, 0}, { 32, 0}, { 32, 0}, { 32, 0}, { 32, 1}, { 31, 0}, { 31, 0}, { 31, 0},
{ 31, 0}, { 31, 0}, { 31, 0}, { 31, 1}, { 30, 0}, { 30, 0}, { 30, 0}, { 30, 0}
};

//unsigned short table_address = (unsigned short)&speed_lookuptable_fast[(unsigned char)(8)][0];
//unsigned short gain = (unsigned short)(table_address + 2);
int main ()
{

unsigned short table_address = (unsigned short)&speed_lookuptable_fast[(unsigned char)(8)][0];

unsigned short gain = (unsigned short)(table_address + 2);
printf("%d\n",gain);
printf("%d\n",table_address);
printf("%p\n",speed_lookuptable_fast);
printf("%p\n",speed_lookuptable_fast+1);
printf("%p\n",&speed_lookuptable_fast[0][1]);
printf("%p\n",&speed_lookuptable_fast[1][0]);
printf("%d\n",(&speed_lookuptable_fast[1][0]+3));
printf("%d\n",speed_lookuptable_fast[8][0]);
printf("%p\n",&speed_lookuptable_fast[8][0]);
printf("%d\n",
(&speed_lookuptable_fast[8][0]+1));

}


转载:https://blog.csdn.net/weixin_44288260/article/details/100932383
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