About%*s and%* s

%*s Usage of

%*s stay scanf In and in printf Different uses in .
1. stay scanf When used in , Added * The part of will be ignored , Will not be obtained by parameters .

for example ：
int a,b;
char b[10];
scanf("%d%*s",&a,b);
// Input is ：123 abc
that 123 The variable... Will be read a in , But the back abc Discard after reading , No variables are given ( For example, the character array here b）

2. stay printf When used in , Represents the position replaced by the following formal parameters , Realize dynamic format output .

for example ：
printf("%*s", 10, s);
// It means output string s, But at least 10 A place , Insufficient in string s Fill in the space on the left , This is equivalent to printf("%10s", s);

%.*s Usage of

* Used to specify the width , Corresponds to an integer .
.（ spot ） Together with the following numbers Is to specify that this width must be output , If the length of the output string is greater than this number , Output by this width , If it is less than , Then the actual length is output

for example ：
int i;
for(i=0;i<3;i++)
printf("%.*s%s\n", i, " ", “########”);
return 0;
// Cycle three times
Do not output spaces for the first time , Direct output ########
Output a space for the second time , Then the output ########
Output two spaces for the third time , Then the output ########