显示转换、隐式转换--精确度、scanf、转义

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显示转换

#include<stdio.h>#include<stdlib.h>void main(){char ch = 'A';//赋值的时候，自动进行数据类型转换/*赋值的时候，自动进行数据类型转换  赋值号会自动将右边转换成左边变量类型  大数据转小数据，小数据也可以转大数据*/short sh = 66;int num = 100.0;double db = 100;double db1 = num + 100.f;printf("ch=%c,sh=%d,num=%d,db=%f,db1=%f",ch,sh,num,db,db1);//保存的时候，保存的是字符的ASICC码，printf("\n%d,%d",sizeof('A'),sizeof(char));printf("\n%d,%d", sizeof(66), sizeof(short));printf("\n%d,%d", sizeof(100.0), sizeof(int));printf("\n%d,%d", sizeof(100), sizeof(double));printf("\n%d,%d", sizeof(num+100.f), sizeof(double));printf("\n%d,%d,%d,%d,%d,%d", sizeof(char), sizeof(short), sizeof(int), sizeof(long), sizeof(float), sizeof(double));getchar();}

ch=A,sh=66,num=100,db=100.000000,db1=200.0000004,14,28,44,84,81,2,4,4,4,8

隐式转换

#include<stdio.h>#include<stdlib.h>void main(){/*char shor直接转为int，32位系统下int和long一样大*/char ch = 'A';short sh = 100;int num = 10000;float fl = 1.000;double db = 10000.000;//'A'首先转换int类型65，在相加得到printf("%d,%d",sizeof(ch+num),ch+num);//short类型转为int类型printf("\n%d,%d",sizeof(sh+num),sh+num);//int类型转为double类型printf("\n%d,%f", sizeof(db + num), db + num);//int类型转为float类型printf("\n%d,%f", sizeof(fl + num), fl + num);//float类型转为double类型printf("\n%d,%f", sizeof(db + fl), db + fl);//转为int,4个字节printf("\n%d,%d", sizeof(ch + sh), ch + sh);unsigned int unum = 4294967000u;int num1 = 100;//打印出-196，说明超出int范围printf("\n%d,%u,%d",sizeof(num1+unum),num1+unum,num1+unum);system("pause");}

4,100654,101008,20000.0000004,10001.0000008,10001.0000004,1654,4294967100,-196请按任意键继续. . .

#define _CRT_SECURE_NO_WARNINGS#include<stdio.h>void main(){float f1 = 9.1234567;//float只能精确到后6位float f2 = 9.12345679f;printf("%f\n",f1);printf("%f\n", f2);if (f1 == f2){printf("f1==f2\n");//相等}/*double类型只能保证小数点15位是正确的，超过的会出现误差*/double d = 1.232534534532423423434;printf("%f\n",d);printf("%.20f\n", d);char str[30] = "calc";printf("我爱%s\n",str);printf(str);/*scanf*/int num;scanf("%d",&num);printf("num=%d",num);/*转衣字符*/printf("%%");//%system("pause");getchar();}

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