#include <stdio.h>
#include <stdlib.h>
int main (int argc, char * argv[]) {
int size;
printf("entry an number of char number: ");
scanf("%d", &size);
// malloc 申请内存, 参数为字节大小, 返回相应类型的指针
char * ptc = (char *) malloc(size * sizeof(char));
printf("entry %d char:", size);
scanf("%s", ptc);
printf("your entry char is: %s\n", ptc);
return 0;
}