C语言编8个程序 比如输入正方形边长求其面积和周长 正方体求体积

// 第一个:求数字位数
#include
#include
#include
#define CRT_SECURE_NO_DEPERCATE
int main(void)
{
int data;
printf("Enter a number:");
scanf("%d",&data);
if (data>=10000)
{printf("Input Error\n");system("pause");exit;}
else if (data>=1000)
printf("The number %4d has 4 numbers.\n");
else if (data>=100)
printf("The number %4d has 3 numbers.\n");
else if (data>=10)
printf("The number %4d has 2 numbers.\n");
else if (data>=1)
printf("The number %4d has 1 numbers.\n");
else {printf("Input Error\n");system("pause");exit;}

system("pause");
return 0;
}

// 第二个24小时制->AM/PM
#include
#include
#include
#define CRT_SECURE_NO_DEPERCATE
int main(void)
{
int hour,minute;
printf("Enter a 24-hour time:");
scanf("%d:%d",&hour,&minute);
switch (hour)
{
case 0:case 1:case 2:case 3:case 4:case 5:case 6:case 7:case 8:case 9:case 10:case 11:case 12:
printf("Equivalent 12-hour time: %-2.2d:%-2.2d AM\n",hour,minute);break;
case 13:case 14:case 15:case 16:case 17:case 18:case 19:case 20:case 21:case 22:case 23:
printf("Equivalent 12-hour time: %-2.2d:%-2.2d PM\n",hour-12,minute);break;
case 24:
printf("Equivalent 12-hour time: 00:%-2.2d AM\n",minute);break;
default:
printf("Input Error\n");system("pause");exit;
}
system("pause");
return 0;
}

// 第三个比较日期前后
#define CRT_SECURE_NO_DEPERCATE
#include
#include
#include
int main(void)
{
int year1,year2,month1,month2,day1,day2,p;
printf("Enter first date (mm/dd/yy):");
scanf("%d/%d/%d",&month1,&day1,&year1);
printf("Enter second date (mm/dd/yy):");
scanf("%d/%d/%d",&month2,&day2,&year2);
if (year1<>year2) p=year1>year2?1:2;
else if (month1<>month2) p=month1>month2?1:2;
else if (day1<>day2) p=day1>day2?1:2;
else p=0;
switch (p)
{
case 1:printf("%2d/%-2.2d/%4d is earlier than %2d/%-2.2d/%4d\n",month2,day2,year2,month1,day1,year1);break;
case 2:printf("%2d/%-2.2d/%4d is earlier than %2d/%-2.2d/%4d\n",month1,day1,year1,month2,day2,year2);break;
case 0:printf("They are definetely equal.\n");break;
}

system("pause");
return 0;
}

// 第四个给分数评级
#define _CRT_SECURE_NO_DEPERCATE /*Before all the includes*/
#include
#include
#include
int main(void)
{
int grade;
_Bool checkpoint;
checkpoint=true;
//Input
while (checkpoint)
{
printf("Enter numerical grade:");
scanf("%d",&grade);
if (grade<0||grade>100) {printf("Input Error,please try again\n");system("pause");}
else if checkpoint=false;
}
//Output
printf("Letter grade: ");
switch (grade/10)
{
case 10: case 9:printf("A");break;
case 8: printf("B");break;
case 7: printf("C");break;
case 6: printf("D");break;
default: printf("F");//Dont wanna a break.....
}
printf("\n");
//Pause
system("pause");
return 0;
}

// 第五个用英文显示数字
#define _CRT_SECURE_NO_DERECATE
#include
#include
#include
int main(void)
{
int input_number,first_digit,second_digit;
bool checkpoint;
//input
checkpoint=true;
while (checkpoint)
{
printf("Enter a two-digit number: ");
scanf("%d",&input_number);
if (input_number<0||input_number>99) {printf("Input Error,please try again.\n");system("pause");}
else checkpoint=false;
}
//output
printf("Your entered the number ");
if (input_number<=19)
switch (input_number) //0-19
{
case 0:printf("zero"); break;
case 1:printf("one"); break;
case 2:printf("two"); break;
case 3:printf("three"); break;
case 4:printf("four"); break;
case 5:printf("five"); break;
case 6:printf("six"); break;
case 7:printf("seven"); break;
case 8:printf("eight"); break;
case 9:printf("nine"); break;
case 10:printf("ten"); break;
case 11:printf("eleven"); break;
case 12:printf("twelve"); break;
case 13:printf("thirteen"); break;
case 14:printf("forteen"); break;
case 15:printf("fifteen"); break;
case 16:printf("sixteen"); break;
case 17:printf("seventeen");break;
case 18:printf("eighteen"); break;
case 19:printf("ninteen"); break;
}
else
{
first_digit=input_number/10;second_digit=input_number%10;
switch (first_digit)
{
case 2:printf("twenty"); break;
case 3:printf("thirty"); break;
case 4:printf("forty"); break;
case 5:printf("fifty"); break;
case 6:printf("sixty"); break;
case 7:printf("seventy");break;
case 8:printf("eighty"); break;
case 9:printf("ninty"); break;
}
switch (second_digit)
{
case 0: ; break;
case 1:printf("-one"); break;
case 2:printf("-two"); break;
case 3:printf("-three"); break;
case 4:printf("-four"); break;
case 5:printf("-five"); break;
case 6:printf("-six"); break;
case 7:printf("-seven"); break;
case 8:printf("-eight"); break;
case 9:printf("-nine"); break;
}
}
printf("\n");

//pause
system("pause");
return 0;
}

// 第六个统计最大数字
#define _CRT_SECURE_NO_DEPRECATE /*Before all the includes*/
#include /*scanf printf*/
#include /*system*/
#include /*bool true false*/
int main(void)
{
float input_data, largest = 0.0f;
printf("This program is used to caculate the largest number you entered.\n");
do
{
printf("Enter a number:");
scanf("%f", &input_data);
if (input_data>largest)
largest = input_data;
} while (input_data>0);
if (largest == 0) printf("Input Error!");
else printf("The largest number entered was %-5.2f\n", largest);
system("pause");
return 0;
}

// 第七个计算最大公约数
#define _CRT_SECURE_NO_DEPRECATE /*Before all the includes*/
#include /*scanf printf*/
#include /*system*/
#include /*bool true false*/
int main(void)
{
int a=0,b=0,t;
bool checkpoint=false;
do
{
printf("Enter two digits:");
scanf("%d%d ",&a,&b);
if (a>=1&&b>=1) checkpoint=true; else printf("Input error, please try again with mind.\n");
}
while (!checkpoint);
if (a while (b!=0)
{
t=a%b;
a=b;
b=t;
}
printf("GCD(Greatest common divisor) is %d\n",a);

system("pause");
return 0;
}

// 第八最简化分数
#define _CRT_SECURE_NO_DEPRECATE /*Before all the includes*/
#include /*scanf printf*/
#include /*system abs*/
#include /*bool true false*/
int main(void)
{
int a=0,b=0,t,point=0,former_a,former_b;
bool checkpoint=false;
do
{
printf("Enter a fraction:");
scanf("%d/%d",&a,&b);
if (b!=0) checkpoint=true; else printf("Input error, please try again with mind.\n");
}
while (!checkpoint);
if (a==0) point=1;
else switch ((a<0)+(b<0))
{
case 1:point=2; /*NO break*/
default:a=abs(a);b=abs(b);
}
printf("In lowest terms: ");
switch (point)
{
case 1:/*a==0*/
printf("0\n");break;
case 2:/*negative*/
printf("-");
case 0:
former_a=a;
former_b=b;
if (a while (b!=0)
{
t=a%b;
a=b;
b=t;
}
former_a=former_a/a;
former_b=former_b/a;
printf("%d",former_a);
if (former_b!=1) printf("/%d",former_b);
printf("\n");
break;/*useless*/
}
system("pause");
return 0;
}