realloc函数

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char ** argv)
{
    char * p = NULL;
    char * q = NULL;
    p = (char*)malloc(20);
    memset(p, 0, 10);
    strcpy(p, "wangxiancai");
    printf("p=[%p],[%s]\n", p, p);
    q = (char*)realloc(p, 30);
    printf("p=[%p],[%s]\n", p, p);
    printf("q=[%p],[%s]\n", q, q);

    return 0;
}