题解 | #替换空格#

char* replaceSpace(char* s)
{
    char* ret = NULL;
    char* tmp = NULL;
    int count = 0;
    char* arr = "%20";
    size_t len = strlen(s);
    char* k = s;
    while (*k != '\0')
    {
        if (*k == ' ')
        {
            count++;
        }
        k++;
    }
    ret = (char*)malloc(len + 3 * count + 1);
    if (ret == NULL)
    {
        perror("malloc");
        return NULL;
    }
    else
    {
        tmp = ret;
    }
    while (*s != '\0')
    {
        if (*s == ' ')
        {
            int i = 0;
            int j = 0;
            char* pr = arr;
            for (i = 0; i < 3; i++)
            {
                *ret = *pr;
                j++;
                if (j == 3)
                {
                    break;
                }
                ret++;
                pr++;
            }
        }
        else
        {
            *ret = *s;
        }
        s++;
        ret++;
    }
    *ret = *s;
    return tmp;
}