C 基础回顾 - 浮点数、字符和字符串

//
//  main.c
//  CFloat
//
//  Created by JakePrim on 2018/7/23.
//  Copyright © 2018年 JakePrim. All rights reserved.
//

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

//浮点数结构体
typedef struct{
    unsigned int nMant : 23; //尾数部分 最大存储23位
    unsigned int nExp : 8;//指数部分 最大存储8位
    unsigned int nSign : 1;//符号位 1位
} FP_SINGLE;

int main(int argc, const char * argv[]) {
    // insert code here...
    //float 始终占用了4个字节 double 始终占用了8个字节
    float a = 0.302f;//小数的默认类型是double，加上后缀f / F 就不用转换了
    float b = 128.11f;
    double c = 123;
    float d = 12.64E3f;
    double e = 0.78e-2;
//    printf("a = %f,b = %f,c = %lf,d = %E,e = %le",a,b,c,d,e);
    printf("a = %g,b = %g,c = %g,d = %g,e = %g \n",a,b,c,d,e);
    
    int g = 1.345; //将小数赋值给整数，直接丢掉小数部分，注意是直接丢掉。
    
    printf("g = %d \n",g);
    
//    char strBin[23] = {0};
    
    float f = 19.625;
//    FP_SINGLE *p = (FP_SINGLE*)&f;
    
//    itoa(p->nSign,strBin,2);
//    sprintf(p->nSign, strBin, 2)
    
    printf("sign:%f \n",f);
    
    //char 字符 只能是对应ASCII的字符
    char a1 = 'a';
    char b1 = '&';
    char c1 = 'X';
    char d1 = ' ';
    
    putchar(a1);
    putchar(b1);
    putchar(c1);
    putchar(d1);
    
    putchar('\n');
    
    printf("a1 = %c,b1 = %c,c1 = %c,d1 = %c \n",a1,b1,c1,d1);
    
    printf("%c %c %-9d \n",'E',71,71);

    //字符串 可以通过字符或指针来间接的存储字符串
    char str[] = "这是数组存储的字符串";
    char *strs = "这是指针存储的字符串";
    puts(str);
    puts(strs);
    
    printf("%s  %s \n",str,strs);
    
    //L 表示的是宽字符 使用UTF-16 UTF-32， 如果不用L前缀 则表示使用ASCII表中的字符
    wchar_t wa = L'中';
    
    wchar_t wb = L'。';
    
    setlocale(LC_ALL, "zh_CN");
    
    putwchar(wa);
    putwchar(wb);
    
    wprintf(L"Wide char %lc %lc",wa,wb);//必须使用宽字符串
    
    //宽字符串
    wchar_t wc[] =L"我是宽字符串数组";
    wchar_t *wd = L"我是宽字符串指针";
    
    wprintf(L"\n 输出宽字符串:wc = %ls ; wd = %ls \n",wc,wd);
    
    char aa1 = '\61';//字符1
    char bb1 = '\141';//字符a
    
    putchar(aa1);
    putchar(bb1);
    
    printf("C\tC++\tJava\n \"c\" frist apperaed \n");
    
    int  aaaas = 0,bbbbs = 0;
    scanf("输入a：%d",&aaaas);
    scanf("输入b:%d",&bbbbs);
    printf("a+b = %d \n",aaaas+bbbbs);
    return 0;
}