
程序代码:
#include <stdio.h>
#include <string.h>
void pick( const char* s, char* sub, size_t beg, size_t end, size_t step )
{
size_t n = strlen(s);
end = end<n ? end : n;
for( size_t i=beg; i<end; i+=step ) // 这里有个bug --- i+=step 可能溢出,明天再改
*sub++ = s[i];
*sub = '\0';
}
int main( void )
{
char sub[100];
pick( "Stringhandling", sub, 2, 8, 2 );
puts( sub );
}