数据类型范围问题
对于以下两个程序：为何前者在测试到m=10000000000时可以正常输出x的值，而第二个程序当测试到m=10000000000时却不能正常输出x的值？

C语言版：

#include<stdio.h>
main() {
float m;int a;
scanf("%d",&a);
while(a--) {
scanf("%f",&m);
printf("%.0f\n",(m-1)*1000+471);}
}

C++版：

#include<iostream>
using namespace std;
main()
{
int a;cin>>a;
double x,m;
while(a--){
cin>>m; x = (m-1)*1000 + 471 ;
cout<<x<<endl;}
}



[解决办法]
跟cout的默认输出格式有关系
试下这个

C/C++ code

……#include<iostream>#include <iomanip>using namespace std;main(){ int a;cin>>a; double x,m; while(a--){  cin>>m; x = (m-1)*1000 + 471 ;  cout<<fixed<<x<<endl; }}
[解决办法]
看lz的c代码是想把小数部分去掉了：
C/C++ code
cout<<fixed<<setprecision(0)<<x<<endl;
[解决办法]
参考float.h：
C/C++ code
...#define DBL_DIG         15                      /* # of decimal digits of precision */#define DBL_EPSILON     2.2204460492503131e-016 /* smallest such that 1.0+DBL_EPSILON != 1.0 */#define DBL_MANT_DIG    53                      /* # of bits in mantissa */#define DBL_MAX         1.7976931348623158e+308 /* max value */#define DBL_MAX_10_EXP  308                     /* max decimal exponent */#define DBL_MAX_EXP     1024                    /* max binary exponent */#define DBL_MIN         2.2250738585072014e-308 /* min positive value */#define DBL_MIN_10_EXP  (-307)                  /* min decimal exponent */#define DBL_MIN_EXP     (-1021)                 /* min binary exponent */#define _DBL_RADIX      2                       /* exponent radix */#define _DBL_ROUNDS     1                       /* addition rounding: near */#define FLT_DIG         6                       /* # of decimal digits of precision */#define FLT_EPSILON     1.192092896e-07F        /* smallest such that 1.0+FLT_EPSILON != 1.0 */#define FLT_GUARD       0#define FLT_MANT_DIG    24                      /* # of bits in mantissa */#define FLT_MAX         3.402823466e+38F        /* max value */#define FLT_MAX_10_EXP  38                      /* max decimal exponent */#define FLT_MAX_EXP     128                     /* max binary exponent */#define FLT_MIN         1.175494351e-38F        /* min positive value */#define FLT_MIN_10_EXP  (-37)                   /* min decimal exponent */#define FLT_MIN_EXP     (-125)                  /* min binary exponent */#define FLT_NORMALIZE   0#define FLT_RADIX       2                       /* exponent radix */#define FLT_ROUNDS      1                       /* addition rounding: near */...