程序侯查看:5 回复:5 评论:5 创建时间:2020-08-05T23:45:47用户:程序侯查看:5 回复:5 评论:5 创建时间:2020-08-05T23:45:47
（其实，还有两个参数没我没都填进去，一个是输出的位置，一个是我也不懂，因为没法实现和不懂没有加进去）
def printf(var):
#我们假设就用C编写python
print(var, end = '')
def Print(*var, sep = ' ', end = '\n'):
for i in range(len(var)):
printf(var[i])
if i < len(var) - 1:
printf(sep)
else:
printf(end)
蒟蒻OIer1048576def Print(*args,sep=" ",end="\n"):
for i in args[:-1]:
printf(i+sep)
print(args[-1]+end)点赞0
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程序侯def Print(*args,sep=" ",end="\n"):
for i in args[:-1]:
printf(i)
printf(sep)
printf(args[-1])
printf(end)点赞0
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tq_xyydef print(*values, sep=' ', end='\n', file=sys.stdout, flush=False):
file.write(sep.join([str(value) for value in values]) + end)
if flush:
file.flush()
print的完整写法
内部是调用C标准库的printf函数实现的。
static char sprint_buf[1024];
int printf(const char *fmt, ...)
{
va_list args;
int n;
va_start(args, fmt);
n = vsprintf(sprint_buf, fmt, args);
va_end(args);
if (console_ops.write)
console_ops.write(sprint_buf, n);
return n;
}
int vsprintf(char *buf, const char *fmt, va_list args)
{
int len;
unsigned long long num;
int i, base;
char * str;
const char *s;
int flags;
int field_width;
int precision;
int qualifier;
for (str=buf ; *fmt ; ++fmt)
{
if (*fmt != '%')
{
*str++ = *fmt;
continue;
}
flags = 0;
repeat:
++fmt;
switch (*fmt)
{
case '-': flags |= LEFT; goto repeat;
case '+': flags |= PLUS; goto repeat;
case ' ': flags |= SPACE; goto repeat;
case '#': flags |= SPECIAL; goto repeat;
case '0': flags |= ZEROPAD; goto repeat;
}
field_width = -1;
if ('0' <= *fmt && *fmt <= '9')
field_width = skip_atoi(&fmt);
else if (*fmt == '*')
{
++fmt;/*skip '*' */
/* it's the next argument */
field_width = va_arg(args, int);
if (field_width < 0) {
field_width = -field_width;
flags |= LEFT;
}
}
precision = -1;
if (*fmt == '.')
{
++fmt;
if ('0' <= *fmt && *fmt <= '9')
precision = skip_atoi(&fmt);
else if (*fmt == '*')
{
++fmt;
/* it's the next argument */
precision = va_arg(args, int);
}
if (precision < 0)
precision = 0;
}
qualifier = -1;
if (*fmt == 'l' && *(fmt + 1) == 'l')
{
qualifier = 'q';
fmt += 2;
}
else if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L'|| *fmt == 'Z')
{
qualifier = *fmt;
++fmt;
}
base = 10;
switch (*fmt)
{
case 'c':
if (!(flags & LEFT))
while (--field_width > 0)
*str++ = ' ';
*str++ = (unsigned char) va_arg(args, int);
while (--field_width > 0)
*str++ = ' ';
continue;
case 's':
s = va_arg(args, char *);
if (!s)
s = "";
len = strnlen(s, precision);
if (!(flags & LEFT))
while (len < field_width--)
*str++ = ' ';
for (i = 0; i < len; ++i)
*str++ = *s++;
while (len < field_width--)
*str++ = ' ';
continue;
case 'p':
if (field_width == -1)
{
field_width = 2*sizeof(void *);
flags |= ZEROPAD;
}
str = number(str,(unsigned long) va_arg(args, void *), 16,
field_width, precision, flags);
continue;
case 'n':
if (qualifier == 'l')
{
long * ip = va_arg(args, long *);
*ip = (str - buf);
}
else if (qualifier == 'Z')
{
size_t * ip = va_arg(args, size_t *);
*ip = (str - buf);
}
else
{
int * ip = va_arg(args, int *);
*ip = (str - buf);
}
continue;
case '%':
*str++ = '%';
continue;
/* integer number formats - set up the flags and "break" */
case 'o':
base = 8;
break;
case 'X':
flags |= LARGE;
case 'x':
base = 16;
break;
case 'd':
case 'i':
flags |= SIGN;
case 'u':
break;
default:
*str++ = '%';
if (*fmt)
*str++ = *fmt;
else
--fmt;
continue;
}
if (qualifier == 'l')
{
num = va_arg(args, unsigned long);
if (flags & SIGN)
num = (signed long) num;
}
else if (qualifier == 'q')
{
num = va_arg(args, unsigned long long);
if (flags & SIGN)
num = (signed long long) num;
}
else if (qualifier == 'Z')
{
num = va_arg(args, size_t);
}
else if (qualifier == 'h')
{
num = (unsigned short) va_arg(args, int);
if (flags & SIGN)
num = (signed short) num;
}
else
{
num = va_arg(args, unsigned int);
if (flags & SIGN)
num = (signed int) num;
}
str = number(str, num, base, field_width, precision, flags);
}
*str = '/0';
return str-buf;
}c函数库printf的实现
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