PX-26-整数常识

1.整数类型包括哪些类型？

 

#include<stdio.h>
#include<limits.h>
void main1()
{
    int a1 = -10;  //十进制的10
    int a2 = 010;        //八进制
    int a3 = 0x10;        //十六进制
    int a4 = 0101u;        //u无符号整数
    int a5 = 0x102l;          //l长整数
    int a6 = 0x103ll;          //long long整数

    //printf("%d", a7);
    getchar();
}

 

2.整数常量

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

void main2()
{

    //嵌入式的场合short int,int可以省略
    short  nummax = SHRT_MAX;//极限
    short  nummin = SHRT_MIN;
    printf("%d", sizeof(short)); //2个字节
    printf("\n%d,%d", nummax, nummin);

    unsigned short numumax = USHRT_MAX;  // 如果越过范围会溢出变成 0
    unsigned short numumin = 0;
    printf("\n%d,%d", numumax, numumin);

    getchar();
}

 

2.在使用时要进行越界的判定

void main3()
{
    int num = 18611210283;     //越过了极限 数据溢出
    printf("%d", num);
    getchar();
}

 

3.long与int是等价的

void main6()
{
    //int    long int在32位以上的机器等价  ，4个字节
    //16位的，int   short int 等价  2个字节
    printf("%d,%d", sizeof(int), sizeof(long));
    int intmax = INT_MAX;
    int intmin = INT_MIN;
    long longmax = LONG_MAX;
    long longmin = LONG_MIN;
    printf("\n%d,%d", intmax, intmin);
    printf("\n%d,%d", longmax, longmin);
      //unsigned int 极大值大于int ,不能表示负数


    signed  int  num1 = 10;     //signed省略，int默认有符号
    unsigned int num2 = 13;

    getchar();
}

 

 

 4. 存储手机号的方式

 

void main()
{
     long long num = 18611210283; //存储QQ号，手机号
     printf("%lld", num);

     unsigned  long long max = ULLONG_MAX;     //存储身份证号
     printf("\n%llu",max);

    getchar();
}

 

 

 代码：

#include<stdio.h>
#include<limits.h>
void main1()
{
    int a1 = -10;  //十进制的10
    int a2 = 010;        //八进制
    int a3 = 0x10;        //十六进制
    int a4 = 0101u;        //u无符号整数
    int a5 = 0x102l;          //l长整数
    int a6 = 0x103ll;          //long long整数

    //printf("%d", a7);
    getchar();
}

void main2()
{
    //嵌入式的场合short int,int可以省略
    short  nummax = SHRT_MAX;//极限
    short  nummin = SHRT_MIN;
    printf("%d", sizeof(short)); //2个字节
    printf("\n%d,%d", nummax, nummin);

    unsigned short numumax = USHRT_MAX;
    unsigned short numumin = 0;
    printf("\n%d,%d", numumax, numumin);

    getchar();
}

void main3()
{
    int num = 18611210283;     //越过了极限
    printf("%d", num);

    getchar();
}


void main6()
{
    //int    long int在32位以上的机器等价  ，4个字节
    //16位的，int   short int 等价  2个字节
    printf("%d,%d", sizeof(int), sizeof(long));
    int intmax = INT_MAX;
    int intmin = INT_MIN;
    long longmax = LONG_MAX;
    long longmin = LONG_MIN;
    printf("\n%d,%d", intmax, intmin);
    printf("\n%d,%d", longmax, longmin);

      //unsigned int 极大值大于int ,不能表示负数

    signed  int  num1 = 10;     //signed省略，int默认有符号
    unsigned int num2 = 13;

    getchar();
}

void main()
{
     long long num = 18611210283; //存储QQ号，手机号
     printf("%lld", num);

     unsigned  long long max = ULLONG_MAX;     //存储身份证号
     printf("\n%llu",max);

    getchar();
}