数据类型自动转换,强制转换.cpp

我正在学习C编程

#include<stdio.h>   /**/
void main()
{
	float PI=3.14159f;
	int s,r=5,t;
	s=r*r*PI;
	printf("\n\n  圆面积为%d\n\n",s);
	t=85;
	printf("  s=%f\n",(float)s);
	printf("  t=%f\n",(double)t);
	printf("  t=%f\n",(float)t);
	printf("  PI=%5.2f\n",PI);
	printf("  PI=%5.2lf\n\n",PI);
	t=(float)2/3;
	printf("  t=(float)2/3=%f\n",t);   //问题?
	printf("  %f\n\n",t);

	float f=5/2;
	printf("  f=5/2=%f---输出实型\n",f);
	printf("  f=5/2=%d----------输出整型\n\n",(int)f);

	int a,b,c;
	printf("  定义:  int a,b,c;\n"); 
	a=5/2; b=5/2.0; c=5%2;
	printf("  a=5/2=%d(输出整型), b=5/2.0=%d(输出整型), c=5%c2=%d(输出整型)=%f(输出实型)\n\n",a,b,'%',c,(float)c);

	float a1,b1;
	printf("  定义:  float a1,b1;\n"); 
	a1=5/2; b1=5/2.0; 
	printf("  a1=5/2=%f(输出实型)=%d(输出整型), b1=5/2.0=%f(输出实型)=%d(输出整型)\n\n",a1,(int)a1,b1,(int)b1);


}