嵌入式学习日志Day3

getchar

#include 
int main
{
	char a = 'A';
	a = getchar();//输入字符
	putchar(a);
    return 0;
}

putchar

#include 
int main
{
	char a = 'A';
	a = getchar();
	putchar(a);//打印字符
    return 0;
}

printf

#include 
int main
{
	char a = 'A';
	a = getchar();
	printf("a = %cn",a);//打印内容
    return 0;
}

scanf

#include 
int main
{
	char a = 'A';
	scanf("%c",&a);//输入内容
	printf("a = %cn",a);
    return 0;
}

gets

#include 
int main
{
	char a[100];
	gets(a);//输入字符串
	puts(a);
    return 0;
}

puts

#include 
int main
{
	char a[100];
	gets(a);
	puts(a);//打印字符串
    return 0;
}

1.用getchar( )清空缓存

int a;
int b;
int c;
scanf("%d%d%d",&a,&b,&c);
//155 452 955
    
char aa;
char bb;
char cc;
char dd;
char ee;
scanf("%c%c%c",&aa,&bb,&cc);
//a b c
dd = getchar();
ee = getchar();

2.计算方程式y=ax^2+bx+c的根

#include
#include //调用sqrt()函数开根号

int main()
{
    double a,b,c;
    double x1,x2;
    scanf("%lf%lf%lf",&a,&b,&c);
    x1 = (-b+sqrt(b*b-4*a*c))/(2*a);
    x2 = (-b-sqrt(b*b-4*a*c))/(2*a);
    printf("x1==%f  x2==%f",x1,x2); 
}

3.大小写字母转换

#include
int main()
{
    char a;
    a = getchar();
    if(('a'<=a)&&('z'>=a))
    {
        a-=32;
    }
    else
    {
        a+=32;
    }
    putchar(a);  
}

4.输入三个数，依次从大到小输出

#include 

int main(int argc, char *argv[])
{ 
    int a,b,c,t;
    printf("请输入三个整数：n");
    scanf("%d%d%d",&a,&b,&c);
    if(a%d>%dn",a,b,c);
    return 0;
} 

5.输入两个数a，b，把a二进制形式从低位到高位第b位，并置一

#include 

int main(int argc, char *argv[])
{ 
    int a,b;
    printf("请输入a:");
    scanf("%d",&a);
    printf("请输入b:");
    scanf("%d",&b);
    a |= 1<<(b-1);
    printf("修正后的数字a为：%dn",a);
    return 0;
} 

6.设置一个简单的计算器，可以实现“+、-、*、/”功能

#include 

int main(int argc, char *argv[])
{ 
    double x,y;
    char c;
    double result;
    printf("请输入：n");
    scanf("%lf%c%lf",&x,&c,&y);
    if(c=='+')
    {
        result = x+y;
        printf("结果等于：%.2fn",result);
    }
    else if(c=='-')
    {
        result = x-y;
        printf("结果等于：%.2fn",result);
    }
    else if(c=='*')
    {
        result = x*y;
        printf("结果等于：%.2fn",result);
    }
    else if(c=='/')
    {
        result = x/y;
        printf("结果等于：%.2fn",result);
    }
    else
    {
        printf("计算错误，请重试！n");
    }
    return 0;
} 

作业：
	给前面讲的输入输出函数每个写几个使用例子。