【工程】十以内加减法辅助教学程序

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void Jiafa();
void Jianfa();
int main()
{
    int n;
    printf("10以内加减法辅助教学程序\n");
    printf("**********************************\n");
    printf("**********************************\n");
    printf("**                              **\n");
    printf("**          1 加法练习          **\n");
    printf("**          2 减法练习          **\n");
    printf("**          3 程序说明          **\n");
    printf("**          4 退出程序          **\n");
    printf("**                              **\n");
    printf("**********************************\n");
    printf("**********************************\n");
    printf("输入菜单项前的数字，选择功能，如数字超过菜单中的范围将显示0\n");
    scanf("%d",&n);
    switch(n)
    {
    case 1:
        system("cls");
         Jiafa();
        break;
    case 2:
        system("cls");
         Jianfa();
        break;
    case 3:
        system("cls");
        printf("该程序的作用为计算10以内加减法");
        break;
    case 4:
        exit(0);
    default:
        printf("选择了功能0");
    }
}
void Jiafa()
{
    int a,b,c,m,counter1=1;
    static int flag=0;
    float counter2=0;
    snack:do{
    srand(time(NULL));
    a=rand()%10;
    b=rand()%10;
    c=a+b;
    }
    while(c>10);
        while(counter1<=5)
     {
        counter1++;
        printf("%d+%d=",a,b);
        scanf("%d",&m);
        if(m==c)
        {
            counter2++;
            flag=1;
            goto snack;
        }
        else
        {
            do{
                counter1++;

                printf("%d+%d=",a,b);
                scanf("%d",&m);
                if(m==c)
                    counter2++;
            }while(m!=c&&counter1<=5);
        }
     }
     if(flag!=1)
       {
        printf("试答的次数太多,正确答案:%d+%d=%d\n",a,b,c);
       }
      printf("正确率为：%.1f",counter2/5);

}
void Jianfa()
{
    int a,b,c,m,counter1=1;
    static int flag=0;
    float counter2=0;
    snack:do{
    srand(time(NULL));
    a=rand()%10;
    b=rand()%10;
    c=a-b;
    }
    while(c<=0);
        while(counter1<=5)
     {
        counter1++;
        printf("%d-%d=",a,b);
        scanf("%d",&m);
        if(m==c)
        {
            flag=1;
            counter2++;
            goto snack;
        }
        else
        {
            do{
                counter1++;

                printf("%d-%d=",a,b);
                scanf("%d",&m);
                if(m==c)
                    counter2++;
            }while(m!=c&&counter1<5);
        }
     }
        if(flag!=1)
        {
            printf("试答的次数太多,正确答案:%d-%d=%d",a,b,c);
        }
        printf("正确率为：%.1f",counter2/5);


}