《算法竞赛入门经典》（第2版）第一章 部分实验题

1.5.2数据类型实验

实验A1：表达式11111*11111的值是多少？把5个1改成6个1呢？9个1呢？

实验A2：把实验A1中的所有数换成浮点数，结果如何？

实验A3：表达式sqrt（-10）的值是多少？尝试用各种方式输出。在计算的过程中系统会报错吗？

实验A4：表达式1.0/0.0、0.0/0.0的值是多少？尝试用各种方式输出。在计算的过程中系统会报错吗？

实验A5：表达式1/0的值是多少？在计算的过程中系统会报错吗？

#include<stdio.h>
#include<math.h>

int main()
{
//A1
printf("%u\n", 11111*11111);
printf("%lu\n", 111111L*111111L); //xxx
printf("%lld\n", 111111111L*111111111L);  //xxx
//A2
printf("%f\n", 11111.0*11111.0);
printf("%lf\n", 111111.0*111111.0); //xxx
printf("%lf\n", 111111111.0*111111111.0);  //xxx
//A3
printf("%f\n", sqrt(-10));
//A4
printf("%u\n", 1.0/0.0);
printf("%f\n", 1.0/0.0);
//A5
// warning: division by zero [-Wdiv-by-zero]
//printf("%u\n", 1/0);
}
/*
123454321
12345654321
12345678987654321
123454321.000000
12345654321.000000
12345678987654320.000000
nan
0
inf
*/

思考问题

问题1：int型整数的最小值和最大值是多少（需要精确值）？

问题2：double型浮点数能精确到多少位小数？或者，这个问题本身值得商榷？

问题3：double型浮点数最大正数值和最小正数值分别是多少（不必特别精确）？

#include<stdio.h>

int main()
{
int max_int = 1, min_int = -1, last_int = 0;
while (max_int > last_int)
{
last_int = max_int;
max_int++;
}
printf("max_int: %d\n", last_int);

last_int = 0;
while (min_int < last_int)
{
last_int = min_int;
min_int--;
}
printf("min_int: %d\n", last_int);

double frac_part = 0.1234567890123456789012345678901234567890f;
printf("%.200lf\n", frac_part);

double max_double = 1, min_u_double = 1, last_double = 0;
while (max_double > last_double)
{
last_double = max_double;
max_double *= 10;
printf("max_double: %lf\n", last_double);
}

last_double = 2;
while (min_u_double < last_double)
{
last_double = min_u_double;
min_u_double /= 10;
printf("min_unsigned double: %.200lf\n", last_double);
}
}
/*
max_int: 2147483647
min_int: -2147483648

0.12345679104328155517578125000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
（小数点8位后就不准了）

max_double: 99999999999999981139503267596847425176765180000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000
max_double: inf

min_unsigned double: 0.00000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
（小数点43位）
*/