#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int sjfu()
{   srand( (unsigned)time( NULL ));
    return rand()%2;
}
int main()
{
    char a[]={'+','-'};
    int b,c,d,t,i,j,f,su=0;
    int daan,fenshu=0;
    printf("--------------------------------------------------------------\n");
    printf("\n\t请输入以下10个计算题的答案\n\t（别着急，每个题有三次输入的机会哦）\n\n");
    printf("--------------------------------------------------------------\n\n");
    for(i=0;i<10;i++)
    {
        srand( (unsigned)time( NULL ));
        b=rand()%51;
        c=rand()%51;
        d=sjfu();
        if(b<c)
        {   t=b;b=c;c=t;}

        switch(a[d])
        {
        case '+':{daan=b+c;break;}
        case '-':{daan=b-c;break;}
        }                                                      //得出算式答案

        if(daan>50)
        {   i-=1;continue;}                                    //判断算式是否符合要求
        su=i;
        printf("第%d题\n",su+1);
        printf("\t%d%c%d=?\n\n",b,a[d],c);                     //输出算式题


        for(j=0;j<3;j++)
        {
        scanf("%d",&f);
        if(f==daan)
            break;
        else
            printf("答案不对哦，再想想看\n");
        }                                                      //用户输入答案（三次机会）

        switch(j)
        {
            case 0:{fenshu+=10;break;}
            case 1:{fenshu+=7;break;}
            case 2:{fenshu+=5;break;}
            case 3:{fenshu+=0;printf("\n\t很可惜\n\t正确答案是 %d\n",daan);break;}
        }                                                      //判断输出该算式答案，并计算得分
        printf("\n--------------------------------------------------------------\n\n");
    }
    if(fenshu>=90)
        printf("SMART\n");
    else if(fenshu<90&&fenshu>=80)
        printf("GOOD\n");
    else if(fenshu<80&&fenshu>=70)
        printf("OK\n");
    else if(fenshu<70&&fenshu>=60)
        printf("PASS\n");
    else
        printf("TRY AGAIN\n");   //判断等级
    return 0;
}