一、强制数据类型转换举例

1.1 double赋值给int

#include<stdio.h>
int main()
{
	double sum = 18, count = 5;
	int mean;
	
	mean = sum / count;
	printf("Value of mean : %d\n", mean);
	
}

执行结果：

double赋值给int，小数部分会删除，会导致数据丢失

1.2 未进行强制数据类型转换

#include<stdio.h>
int main()
{
	int sum = 18, count = 5;
	double mean;
	
	mean = sum / count;
	printf("Value of sum / count : %d\n", (sum / count));
	printf("Value of mean : %d\n", mean);
	
}

执行结果：

未进行类型强制转换，整型赋值给double，结果为0

1.3 进行强制数据类型转换

#include<stdio.h>
int main()
{
	int sum = 18, count = 5;
	double mean;
	
	mean = (double)sum / count;
	printf("Value of sum / count : %d\n", (sum / count));
	printf("Value of mean : %f\n", mean);
	
}

执行结果：

强制转为double，输出正确结果

二、整数提升

三、常用的算术转换

整数强制转换为浮点数