1.
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int main()
{
double x,y;
scanf("%lf",&x);
if(x!=0)
{
if(x<1)
y=log10(x);
else if(x<6)
y=sqrt(2*x+3);
else
y=pow(x,5.0)+pow(x,3.0)*3;
printf("y=%.4lf\n",y);
}
else
printf("error!\n");
system("pause");
return 0;
}
2.
#include <stdio.h>
#include<stdlib.h>
int main()
{
float x,y,z;
char f;
scanf("%f%c%f",&x,&f,&y);
switch(f)
{
case '+':z=x+y;break;
case '-':z=x-y;break;
case '*':z=x*y;break;
case '/':if(y==0)printf("出错,除数为零?\n");else z=x/y;break;
default:printf("不是四则运算式\n");break;
}
if(!(f=='/'&&y==0)&&(f=='+'||f=='+'||f=='-'||f=='*'||f=='/'))
printf("%.2f%c%.2f=%.4f\n",x,f,y,z);
system("pause");
return 0;
}
3.
#include<stdio.h>
#include<stdlib.h>
int main()
{
int t;
scanf("%d",&t);
if(t>0)
{
switch(t%7)
{
case 0:printf("星期日\n");break;
case 1:printf("星期一\n");break;
case 2:printf("星期二\n");break;
case 3:printf("星期三\n");break;
case 4:printf("星期四\n");break;
case 5:printf("星期五\n");break;
case 6:printf("星期六\n");break;
default:break;
}}else
printf("错误!请重新运行程序!\n");
system("pause");
return 0;
}
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int main()
{
double x,y;
scanf("%lf",&x);
if(x!=0)
{
if(x<1)
y=log10(x);
else if(x<6)
y=sqrt(2*x+3);
else
y=pow(x,5.0)+pow(x,3.0)*3;
printf("y=%.4lf\n",y);
}
else
printf("error!\n");
system("pause");
return 0;
}
2.
#include <stdio.h>
#include<stdlib.h>
int main()
{
float x,y,z;
char f;
scanf("%f%c%f",&x,&f,&y);
switch(f)
{
case '+':z=x+y;break;
case '-':z=x-y;break;
case '*':z=x*y;break;
case '/':if(y==0)printf("出错,除数为零?\n");else z=x/y;break;
default:printf("不是四则运算式\n");break;
}
if(!(f=='/'&&y==0)&&(f=='+'||f=='+'||f=='-'||f=='*'||f=='/'))
printf("%.2f%c%.2f=%.4f\n",x,f,y,z);
system("pause");
return 0;
}
3.
#include<stdio.h>
#include<stdlib.h>
int main()
{
int t;
scanf("%d",&t);
if(t>0)
{
switch(t%7)
{
case 0:printf("星期日\n");break;
case 1:printf("星期一\n");break;
case 2:printf("星期二\n");break;
case 3:printf("星期三\n");break;
case 4:printf("星期四\n");break;
case 5:printf("星期五\n");break;
case 6:printf("星期六\n");break;
default:break;
}}else
printf("错误!请重新运行程序!\n");
system("pause");
return 0;
}