如何保证输出float类型的整数位，舍弃所有小数位值并填充数字0？

[uison]

如题！新手求帮助。我定义了一个float a，但是输出时想舍弃小数位的值填充相应的数字0。
比如输入128显示128.0，输入128.6则显示128.0
新手刚开始看，哈哈哈。

[赵4老师]

floor
Calculates the floor of a value.

double floor( double x );

Function Required Header Compatibility
floor <math.h> ANSI, Win 95, Win NT


For additional compatibility information, see Compatibility in the Introduction.

Libraries

LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version


Return Value

The floor function returns a floating-point value representing the largest integer that is less than or equal to x.There is no error return.

Parameter

x

Floating-point value

Example

/* FLOOR.C: This example displays the largest integers
* less than or equal to the floating-point values 2.8
* and -2.8. It then shows the smallest integers greater
* than or equal to 2.8 and -2.8.
*/

#include <math.h>
#include <stdio.h>

void main( void )
{
double y;

y = floor( 2.8 );
printf( "The floor of 2.8 is %f\n", y );
y = floor( -2.8 );
printf( "The floor of -2.8 is %f\n", y );

y = ceil( 2.8 );
printf( "The ceil of 2.8 is %f\n", y );
y = ceil( -2.8 );
printf( "The ceil of -2.8 is %f\n", y );
}


Output

The floor of 2.8 is 2.000000
The floor of -2.8 is -3.000000
The ceil of 2.8 is 3.000000
The ceil of -2.8 is -2.000000


Floating-Point Support Routines

See Also ceil, fmod

[赵4老师]

modf
Splits a floating-point value into fractional and integer parts.

double modf( double x, double *intptr );

Routine Required Header Compatibility
modf <math.h> ANSI, Win 95, Win NT


For additional compatibility information, see Compatibility in the Introduction.

Libraries

LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version


Return Value

This function returns the signed fractional portion of x. There is no error return.

Parameters

x

Floating-point value

intptr

Pointer to stored integer portion

Remarks

The modf function breaks down the floating-point value x into fractional and integer parts, each of which has the same sign as x. The signed fractional portion of x is returned. The integer portion is stored as a floating-point value at intptr.

Example

/* MODF.C */

#include <math.h>
#include <stdio.h>

void main( void )
{
double x, y, n;

x = -14.87654321; /* Divide x into its fractional */
y = modf( x, &n ); /* and integer parts */

printf( "For %f, the fraction is %f and the integer is %.f\n",
x, y, n );
}


Output

For -14.876543, the fraction is -0.876543 and the integer is -14


Floating-Point Support Routines, Long Double

See Also frexp, ldexp

[zangfong]

偷懒一点，如果按照楼主的意思，直接抹去小数点后的数字而填充0的话，直接

printf("%d.0\n",(int)a);

头文件都省了

[zangfong]

恩，赵老师说的对，不然就多了一个bug

[赵4老师]

引用 4 楼 zangfong 的回复:

偷懒一点，如果按照楼主的意思，直接抹去小数点后的数字而填充0的话，直接

printf("%d.0\n",(int)a);

头文件都省了

别忘了float能表示的数范围。

[辶井]

把float a改成int a，在输出的时候再强转float