【C语言】练习2-1

2022-07-18 11:52:46

题目来源：《The C programming language》中的习题P27
练习2-1： 编写一个程序以确定分别由signed及unsigned限定的char、short、int与long类型变量的取值范围。采用打印标准头文件中的相应值以及直接计算两种方式实现。后一种方法的实现较困难一些，因为要确定各种浮点类型的取值范围。

　　采用打印标准头文件中的相应值：

#include <stdio.h>
#include <limits.h>

int main()
{
    printf("采用打印标准头文件limits.h中的相应值：\n");
    //signed types
    printf("signed char min = %d\n", SCHAR_MIN);
    printf("signed char max = %d\n", SCHAR_MAX);
    printf("signed short min = %d\n", SHRT_MIN);
    printf("signed short max = %d\n", SHRT_MAX);
    printf("signed int min = %d\n", INT_MIN);
    printf("signed int max = %d\n", INT_MAX);
    printf("signed long min = %ld\n", LONG_MIN);
    printf("signed long max = %ld\n", LONG_MAX);
    //unsigned types
    printf("unsigned char max = %u\n", UCHAR_MAX);
    printf("unsigned short max = %u\n", USHRT_MAX);
    printf("unsigned int max = %u\n", UINT_MAX);
    printf("unsigned long max = %lu\n", ULONG_MAX);
    return 0;
}

　　执行结果：

　　直接计算的方式：

#include <stdio.h>
//determine ranges of types
int main()
{
printf("采用直接计算的方式：\n");
//signed types
printf("signed char min = %d\n", -(char)((unsigned char)~0>>1)-1);
printf("signed char max = %d\n", (char)((unsigned char)~0>>1));
printf("signed short min = %d\n", -(short)((unsigned short)~0>>1)-1);
printf("signed short max = %d\n", (short)((unsigned short)~0>>1));
printf("signed int min = %d\n", -(int)((unsigned int)~0>>1)-1);
printf("signed int max = %d\n", (int)((unsigned int)~0>>1));
printf("signed long min = %ld\n", -(long)((unsigned long)~0>>1)-1);
printf("signed long max = %ld\n", (long)((unsigned long)~0>>1));
//unsigned types
printf("unsigned char max = %u\n", (unsigned char)~0);
printf("unsigned short max = %u\n", (unsigned short)~0);
printf("unsigned int max = %u\n", (unsigned int)~0);
printf("unsigned long max = %lu\n", (unsigned long)~0);
return 0;
}