面试题：空格替换字符

#include <stdio.h>

#include <stdlib.h>

void replace_blank(char *p)

{

int len = 0;

int newlen = 0；

       int blank_count = 0;

char *pstr = p;

while (*pstr)

{

if (*pstr == ' ')

blank_count++;

len++;

pstr++;

}

newlen = len + 2 * blank_count;

while (len < newlen)

{

if (p[len] == ' ')

{

p[newlen--] = '0';

p[newlen--] = '2';

p[newlen--] = '%';

}

else

{

p[newlen--] = p[len];

}

len--;

}

}

int main()

{

char p[20] = "we are happy.";

replace_blank(p);

printf("%s\n", p);

system("pause");

return 0;

}