C 学习笔记

Perfect Code Can Say Anything

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eg1:

int array[10]={9}  array=9 0 0 0 0 0 0 0 0 0 

int array[0]={0} array=0 0 0 0 0 0 0 0 0 0

++array[0]  =>  get the array[0] number and increase. and result array[0] value is 1

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eg2.

//count the number's times

　　int c=0

　　int array[10];

　　while((c=getchar())!=EOF){

　　　　if(c>='0'&&c<='9')

　　　　{

　　　　++array[c-'0'] ;

　　　　}

　   }  

"hello\n"  --------->h    e   l    l   o    \n    \0

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eg3

int getline(char s[],lim)

for(i=0;i<lim-1&&(c=getchar())!=EOF&&c!='\n';i++)

{s[i]=c;}

if(c=='\n') s[i]=c

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void copy(char to[] ,char from[])

{

int i=0;

while((to[i]=from[i])!='\0'){

i++;

}

}

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 int *pa  

int a[10]

a[1] is diffreent from a  ====>a[1] is a int number and a is a pointer

a is a pointer so   pa=a    equal pa=&a[0]    and a[i] equal   *(a+i)

a[0] equal  *pa      ====>a[i]  equal  pa[i]

char *s equal char s[]

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char amessage[]="Hello C"         can be modified    it's an array

char *amessage="Hello C"         can't  be modified  string const