C语言（第四章）

#include<stdio.h>
int main()
{
  int a,b,c,max;
  printf("请输入三个整数，以逗号隔开\n");
  scanf("%d,%d,%d",&a,&b,&c);
  max=a;
  if(b>max)
	  max=b;
  if(c>max)
	  max=c;
  printf("最大值为%d",max);
  return 0;
}

5
求平方根

#include<stdio.h>
#include<math.h>
int main()
{
	int a,gen;
     printf("请输入一个小于1000的正数");
		scanf("%d",&a);
if(a>1000)
	{printf("请重输\n");
	 scanf("%d",&a);
	}
gen=sqrt(a);
  printf("%d平方根为%d",a,gen);
  return 0;
}

6
x (x<1)
y=2x-1(1<=x<10)
3x-11(x>=10)

   #include<stdio.h>
int main()
{
  int x,y;
  printf("input independent variable");
  scanf("%d",&x);
  if(x<1)
     y=x;
  else if(x<10)
	  y=2*x-1;
  else
	  y=3*x-11;
  printf("the dependent variablr is %d\n",y);
  return 0;
}

7

#include<stdio.h>
int main()
{
  int x,y;
  printf("input independent variable");
  scanf("%d",&x);
  if(x<0)
     y=-1;
  else if(x=0)
	  y=0;
  else
	  y=1;
  printf("the dependent variablr is %d\n",y);
  return 0;
}

8
成绩转换

#include<stdio.h>
int main()
{
  float i;
  printf("input Percentage achievement ");
  scanf("%d",&i);
  if(i<60)
	  printf("the achievement is E\n");
  else if(i<70)
	    printf("the achievement is D\n");
  else if(i<80)
	    printf("the achievement is C\n");
 else if(i<90)
	    printf("the achievement is B\n");
  else 
	    printf("the achievement is A\n");
  return 0;

}