关于浮点数格式运算与定义时应注意的点

#include <stdio.h>
int main()
{
double a=3./4;
double b=3/4;
double c=3/4.;
double d=3./4.;
printf("%f\n",a);
printf("%f\n",b);
printf("%f\n",c);
printf("%f\n",d);
return 0;
}

//运算结果分别为
0.750000
0.000000
0.750000
0.750000
用算式定义时需注意3.为浮点数格式的3
而整数会被隐信转换为浮点数格式。

#include <stdio.h>
int main()
{ int a, b,c,d,e; double f,g,h,m;
f = 0.0; a = 5; b = 4;
g = a/b;
h = (double) a/b;
a = (double) a/b;

printf("(double)a/b = %f\n",h);
printf("g = %f\n",g);
printf("a = %f\n",a);
printf("a = %f\n",(double)a);
printf("a = %d\n",(double)a);
return 0;

}
//运算结果分别为
(double)a/b = 1.250000
g = 1.000000
a = 0.000000
a = 1.000000
a = 0

用浮点数类型才可完整表达双精度计算后的数值
并且浮点数类型不能用整数输出，输出固定为0
一般不做int转换为float类型