把一个字符串中的所有的空格替换成“%20”

void replace(char str[], int size){    char *p = str;    int count = 0;    int i = 0;    int newsize = 0;    for (i = 0; i < size; ++i)    {        if (str[i] == ' ')            count++;    }    newsize = size + count * 2 - 1;    for (i = size - 1; i >= 0; --i)    {        if (p[i] == ' ')        {            str[newsize] = '0';            newsize--;            str[newsize] = '2';            newsize--;            str[newsize] = '%';            newsize--;        }        else        {            str[newsize] = p[i];            newsize--;        }    }}int main(){    char arr[100] = "my name is tian";    int sz = strlen(arr);    replace(arr, sz);    printf("%s", arr);    system("pause");    return 0;}