example.c

#include <stdio.h>
int main ()
{
    float h,r,l,s,sq,vq,vz;
	float pi=3.141526;
	printf("请输入圆半径r，圆柱高h∶");
	scanf("%f,%f",&r,&h);               //要求输入圆半径r和圆柱高h 
	l=2*pi*r;                          //计算圆周长l
	s=r*r*pi;                          //计算圆面积s
	sq=4*pi*r*r;                       //计算圆球表面积sq
	vq=4.0/3.0*pi*r*r*r;               //计算圆球体积vq
	vz=pi*r*r*h;                       //计算圆柱体积vz
	printf("圆周长为:       l=%6.2f\n",l);
	printf("圆面积为:       s=%6.2f\n",s); 
	printf("圆球表面积为:   sq=%6.2f\n",sq);
	printf("圆球体积为:     v=%6.2f\n",vq);
	printf("圆柱体积为:     vz=%6.2f\n",vz);
	return 0;
}

#include <stdio.h>
int main()
{ 
	int x,y;
	printf("输入x:");
	scanf("%d",&x);
	if(x<1)               /* x<1 */
	{ 
		y=x;
		printf("x=%3d,   y=x=%d\n" ,x,y);
	}
	else  if(x<10)        /* 1=<x<10 */
	{
		y=2*x-1;
		printf("x=%d,  y=2*x-1=%d\n",x,y);
	}
	else            /* x>=10  */
	{ 
		y=3*x-11;
		printf("x=%d,  y=3*x-11=%d\n",x,y);
	}
	return 0;
}

#include <stdio.h>
int main()
{
	float score;
	char grade;
	printf("请输入学生成绩:");
	scanf("%f",&score);
	while (score>100||score<0)
	{
		printf("\n 输入有误,请重输");
		scanf("%f",&score);
	}
	switch((int)(score/10))
	{
		case 10: grade='A';break;
		case 9: grade='A';break;
		case 8: grade='B';break;
		case 7: grade='C';break;
		case 6: grade='D';break;
		default: grade='E';
	}
	printf("成绩是 %5.1f,相应的等级是%c\n ",score,grade);
	return 0;
}

#include <stdio.h>
int main()
{
	int  p,r,n,m,temp;
	printf("请输入两个正整数n,m:");
	scanf("%d,%d,",&n,&m);
	if (n<m)
	{
		temp=n;
		n=m;
		m=temp;
	}
	p=n*m;
	while(m!=0)
	{
		r=n%m;
		n=m;
		m=r;
	}
	printf("它们的最大公约数为:%d\n",n);
	printf("它们的最小公约数为:%d\n",p/n);
	return 0;
}

#include <stdio.h>
#include <math.h>
int main()
{
	float a,x0,x1;
	printf("enter a positive number:");
	scanf("%f",&a);
	x0=a/2;
	x1=(x0+a/x0)/2;
	do
	{
		x0=x1;
		x1=(x0+a/x0)/2;
	}while(fabs(x0-x1)>=1e-5);
	printf("The square root of %5.2f  is %8.5f\n",a,x1);
	return 0;
}

#include <stdio.h>
int main()
{
	int i,j,min,temp,a[11];
	printf("enter data:\n");
	for (i=1;i<=10;i++)
	{
		printf("a[%d]=",i);
		scanf("%d",&a[i]);
	}
	printf("\n");
	printf("The orginal numbers:\n"); 
	for (i=1;i<=10;i++)
		printf("%5d",a[i]);
	printf("\n");
	for (i=1;i<=9;i++)
	{
		min=i;
		for (j=i+1;j<=10;j++)
			if (a[min]>a[j]) min=j;
		temp=a[i];
		a[i]=a[min];
		a[min]=temp;
	}
	printf("\nThe sorted numbers:\n");
	for (i=1;i<=10;i++)
		printf("%5d",a[i]);
	printf("\n");
	return 0;
}

#include <stdio.h>
int main()
{
	int i,j,upp,low,dig,spa,oth;
	char text[3][80];
	upp=low=dig=spa=oth=0;
	for (i=0;i<3;i++)
	{
	       	printf("please input line %d:\n",i+1);
		gets(text[i]);
		for (j=0;j<80 && text[i][j]!='\0';j++)
		{
			if (text[i][j]>='A'&& text[i][j]<='Z')
				upp++;
			else if (text[i][j]>='a' && text[i][j]<='z')
				low++;
			else if (text[i][j]>='0' && text[i][j]<='9')
				dig++;
			else if (text[i][j]==' ')
				spa++;
			else
				oth++;
		}
	}
	printf("\nupper case: %d\n",upp);
	printf("lower case: %d\n",low);
	printf("digit     : %d\n",dig);
	printf("space     : %d\n",spa);
	printf("other     : %d\n",oth);
	return 0;
}

#include <stdio.h>
#include <math.h>
float x1,x2,disc,p,q;
int main()
{
	void greater_than_zero(float,float);
	void equal_to_zero(float,float);
	void smaller_than_zero(float,float);
	float a,b,c;
	printf("input a,b,c:");
	scanf("%f,%f,%f",&a,&b,&c);
	printf("equation: %5.2f*x*x+%5.2f*x+%5.2f=0\n",a,b,c);
	disc=b*b-4*a*c;
	printf("root:\n");
	if (disc>0)
	{
		greater_than_zero(a,b);
		printf("x1=%f\t\tx2=%f\n",x1,x2);
	}
	else if (disc==0)
	{
		equal_to_zero(a,b);
		printf("x1=%f\t\tx2=%f\n",x1,x2);
	}
	else
	{
		smaller_than_zero(a,b);
		printf("x1=%f+%fi\tx2=%f-%fi\n",p,q,p,q);
	}
	return 0;
}

void greater_than_zero(float a,float b)
{
	x1=(-b+sqrt(disc))/(2*a);
	x2=(-b-sqrt(disc))/(2*a);
}

void equal_to_zero(float a,float b)
{
	x1=x2=(-b)/(2*a);
}

void smaller_than_zero(float a,float b)
{
	p=-b/(2*a);
	q=sqrt(-disc)/(2*a);
}

#include <stdio.h>
#include <string.h>
#define N 10
char str[N];
int main()
{
	void sort(char []);
	int i,flag;
	for (flag=1;flag==1;)
	{
		printf("input string:\n");
		scanf("%s",&str);
		if (strlen(str)>N)
			printf("string too long,input again!");
		else
			flag=0;
	}
	sort(str);
	printf("string sorted:\n");
	for (i=0;i<N;i++)
		printf("%c",str[i]);
	printf("\n");
	return 0;
}

void sort(char str[])
{
	int i,j;
	char t;
	for(j=1;j<N;j++)
		for (i=0;(i<N-j)&&(str[i]!='\0');i++)
			if(str[i]>str[i+1])
			{
				t=str[i];
				str[i]=str[i+1];
				str[i+1]=t;
			}
}