闲来无事，写了个小的个人计算器。

觉得好玩的直接复制拿走。

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#define PI 3.14
int jf()
{int a1,b1,a2,b2,m,n,i;printf("请以“1/8 1/9”为例输入两个分数\n");scanf("%d/%d",&a1,&b1);scanf("%d/%d",&a2,&b2);m=b1*b2;n=a1*b2+a2*b1;if(n%m==0)printf("%d",n/m);else{for(i=2;i<=m&&i<=n;i++){if(n%i==0&&m%i==0){n=n/i;m=m/i;i--;}}printf("%d/%d\n ",n,m);}return 0;
}
int zuida()//求八个整数的最大值
{int i,j,arr[2][4],max=0;printf("请输入八个整数，以空格分隔！\n");for(i=0;i<=1;i++){for(j=0;j<=3;j++){scanf("%d",&arr[i][j]);}printf("\n");printf("--------------------------\n");}for(i=0;i<=1;i++){for(j=0;j<=3;j++){if(arr[i][j]>max){max=arr[i][j];}}}return max;
}
long f(int n)//求一个数的阶乘
{if(n<0||n>12)printf("n<0,input error\n");else if(n==0||n==1)return (1);elsereturn(n*(f(n-1))); 
}
double qiu(double r)//球体体积
{return ((4.0/3)*PI*pow(r,3));
}
double yuanzhu()//圆柱体积
{double i,h,j;printf("请按“A B”的形式依次输入圆柱的底面半径和高\n");scanf("%lf %lf",&i,&h);printf("--------------------------\n");j=(PI*pow(i,2)*h);return j;
}
int main()
{while(1){int x,n;long result;int i,j;double r;printf("				------个人计算器------\n");printf("请选择：\n");printf("1,圆柱体积   2,球体体积  3,乘法口诀表  4,加法口诀表  5,求一个数的阶乘  6,求八个整数的最大值 7.有理数加法\n");scanf("%d",&x);switch(x){case 7:jf();break;case 6:printf("八个数中的最大值为：%d\n",zuida());printf("--------------------------\n");break;case 5:printf("Input a integre numbers(0<=n<=12)\n");scanf("%d",&n);result=f(n);printf("%d!=%ld\n",n,result);break;case 4://加法口诀表for(i=1;i<10;i++){for(j=i;j>0;j--){printf("%d+%d=%d ",i,j,i+j);}printf("\n");}break;case 3://乘法口诀表for(i=1;i<10;i++){for(j=i;j>0;j--){printf("%d*%d=%d ",i,j,i*j);}printf("\n");}break;case 2:printf("请输入球体半径：\n");scanf("%lf",&r);printf("--------------------------\n");printf("球体体积为：%.2lf\n",qiu(r));printf("--------------------------\n");break;case 1:printf("圆柱体积为：%.2lf\n",yuanzhu());printf("--------------------------\n");break;default:printf("输入错误，请重新输入！\n");}system("pause");//暂停函数system("cls");//清屏函数}return 0;
}