我有时间就把自己写的代码发上来,供大家品评

如果你有更好的更精妙的算法请不吝赐教,谢谢!

4位以内数由小到大排序
main()
{
int a,b,c,d,x;
printf("input four numbers:");
scanf("%d,%d,%d,%d",&a,&b,&c,&d);
if(a>b)
{x=a;a=b;b=x;}
if(a>c)
{x=a;a=c;c=x;}
if(a>d)
{x=a;a=d;d=x;}
if(b>c)
{x=b;b=c;c=x;}
if(b>d)
{x=b;b=d;d=x;}
if(c>d)
{x=c;c=d;d=x;}
printf("%d,%d,%d,%d",a,b,c,d);
}

if给出成绩输出等级
main()
{
 int num;
 char a,b,c,d,e;
 a='A';
 b='B';
 c='C';
 d='D';
 e='E';
 printf("please input a score(0~100):");
 scanf("%d",&num);
if(num>=0&&num<=100)         /*检验数据合法否*/
 if(num>89)
  printf("grade is %c",a);
else
 if(num<60)
  printf("grade is %c",e);
else
 if(num<90&&num>79)
  printf("grade is %c",b);
else
 if(num<80&&num>69)
  printf("grade is %c",c);
else
  printf("grade is %c",d);
else printf("The score error");
}

switch给成绩输出等级


main()
{
 int  score, grade;
 printf("Input a score(0~100): ");
 scanf("%d", &score);
 grade = score/10;     /*将成绩整除10，转化成switch语句中的case标号*/
 switch (grade)
{
    case  10:
    case   9: printf("grade=A\n"); break;  /*标号10和9，都执行本行的2条语句*/
    case   8: printf("grade=B\n"); break;
    case   7: printf("grade=C\n"); break;
    case   6: printf("grade=D\n"); break;
    case   5:
    case   4:
    case   3:
    case   2:
    case   1:
    case   0: printf("grade=E\n"); break;  /*标号5、4、3、2、1和0，都执行本行的2条语句*/
    default: printf("The score is out of range!\n"); /*成绩超出范围时，提示出错*/
}
}

叛断某一年是否润年


#include<stdio.h>
main()
{
 int year,leap=0;                              /*预制为非润年*/
 printf("please input the year:");
 scanf("%d",&year);
if(year%4==0)
  if(year%100!=0) leap=1;
else
  if(year%400==0) leap=1;
if(leap)
  printf("%d is a leap year\n",year);
else
  printf("%d is a not leap year\n",year);
}