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网易云课堂_艾叔：零基础一站式C语言|C程序设计精讲_章节5整型_课时41整型转换、扩展与截断

2024-08-26 09:50:18   217人阅读

 

扩展：

char src;

int dst;

dst = (char)src;

src有符号，扩展位=符号位，符号位0扩展位也是0，符号位1扩展位也是1

src无符号，扩展位=0

 

截断：

int src;

char dst;

dst =(char)src;

从低字节开始，截取sizeof(dst)个字节的十六进制数值

 

整型转换，只与十六进制数值有关系

int i = -1;

整数-1

0xFFFFFFFF十六进制数值

 

扩展：

 

int to unsigned int

 

#include <stdio.h>
#include <stdlib.h>

int main()
{
	int int_num = -1;
	unsigned int uint_num = (unsigned int)int_num;//强制转换，显式转换

	printf("%x %d\n", int_num, int_num);
	printf("%x %u\n", uint_num, uint_num);

	system("pause");

	return 0;
}

 

ffffffff -1
ffffffff 4294967295
请按任意键继续. . .

 

char to int

char to unsigned int

 

#include <stdio.h>
#include <stdlib.h>

int main()
{
	char char_num = -1;
	int int_num = (int)char_num;
	unsigned int uint_num = (unsigned int)char_num;

	printf("%hhx %hhd\n", char_num, char_num);
	printf("%x %d\n", int_num, int_num);
	printf("%x %u\n", uint_num, uint_num);

	system("pause");

	return 0;
}

 

ff -1
ffffffff -1
ffffffff 4294967295
请按任意键继续. . .

 

char to int

char to unsigned int

 

#include <stdio.h>
#include <stdlib.h>

int main()
{
	char char_num = 1;
	int int_num = (int)char_num;
	unsigned int uint_num = (unsigned int)char_num;

	printf("%hhx %hhd\n", char_num, char_num);
	printf("%x %d\n", int_num, int_num);
	printf("%x %u\n", uint_num, uint_num);

	system("pause");

	return 0;
}

 

1 1
1 1
1 1
请按任意键继续. . .

 

unsigned char to int

unsigned char to unsigned int

 

#include <stdio.h>
#include <stdlib.h>

int main()
{
	unsigned char char_num = 0xFF;
	int int_num = (int)char_num;
	unsigned int uint_num = (unsigned int)char_num;

	printf("%hhx %hhd\n", char_num, char_num);
	printf("%x %d\n", int_num, int_num);
	printf("%x %u\n", uint_num, uint_num);

	system("pause");

	return 0;
}

 

ff -1
ff 255
ff 255
请按任意键继续. . .

 

截断：

 

#include <stdio.h>
#include <stdlib.h>

int main()
{
	int int_num = -0x12345678;
	short short_num = (short)int_num;
	unsigned short unshort_num = (unsigned short)int_num;

	printf("int %x %d\n", int_num, int_num);
	printf("short %hx %hd\n", short_num, short_num);
	printf("unshort %hx %hu\n", unshort_num, unshort_num);

	system("pause");

	return 0;
}

 

int edcba988 -305419896
short a988 -22136
unshort a988 43400
请按任意键继续. . .

 

网易云课堂_艾叔：零基础一站式C语言|C程序设计精讲_章节5整型_课时41整型转换、扩展与截断


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