POJ 2577: Interpreter

//POJ 2577
//题意：按题意实现一个解释器。模拟以前的某种计算机的CPU吧
//题型：简单模拟题
//思路：有条理就行
#include <cstdio>
#include <cstring>

int hotal[10];
int memory[1000];
int runedCommandNum;

//读入本行数字，储存在对应内存位置
//若为空行，返回false
bool readIntInThisLine(int nowPosition) {
    char now;
    int num = 0;

    now = getchar();
    if (now == ‘\n‘) return false;
    if (now == EOF) return false;

    while (now != ‘\n‘) {
        num = num*10 + now-‘0‘;
        now = getchar();
    }
    memory[nowPosition] = num%1000;
    //printf("read %d (positon:%d[%d])\n", num%1000, nowPosition, memory[nowPosition]);
    return true;
}

//执行命令
//描述：从指定内存处执行命令，并通过参数返回下一条命令所在内存。
//      如果停机，返回false
bool runCommandAt(int nowPosition, int &nextPosition) {
    char command[10]; 
    sprintf(command, "%03d", memory[nowPosition]);
    //printf("command = %s\n", command);

    nextPosition = nowPosition+1;
    switch (command[0]) {
        case ‘1‘:
            //如果后面不是00，那是什么命令
            if (command[1] == ‘0‘ && command[2] == ‘0‘) return false;
            else return true;
        case ‘2‘:
            hotal[command[1]-‘0‘] = command[2]-‘0‘;
            hotal[command[1]-‘0‘] %= 1000;
            return true;
        case ‘3‘:
            hotal[command[1]-‘0‘] += command[2]-‘0‘;
            hotal[command[1]-‘0‘] %= 1000;
            return true;
        case ‘4‘:
            hotal[command[1]-‘0‘] *= command[2]-‘0‘;
            hotal[command[1]-‘0‘] %= 1000;
            return true;
        case ‘5‘:
            hotal[command[1]-‘0‘] = hotal[command[2]-‘0‘];
            hotal[command[1]-‘0‘] %= 1000;
            return true;
        case ‘6‘:
            hotal[command[1]-‘0‘] += hotal[command[2]-‘0‘];
            hotal[command[1]-‘0‘] %= 1000;
            return true;
        case ‘7‘:
            hotal[command[1]-‘0‘] *= hotal[command[2]-‘0‘];
            hotal[command[1]-‘0‘] %= 1000;
            return true;
        case ‘8‘:
            hotal[command[1]-‘0‘] = memory[hotal[command[2]-‘0‘]];
            hotal[command[1]-‘0‘] %= 1000;
            return true;
        case ‘9‘:
            memory[hotal[command[2]-‘0‘]] = hotal[command[1]-‘0‘] ;
            memory[hotal[command[2]-‘0‘]] %= 1000;
            return true;
        case ‘0‘:
            if (hotal[command[2]-‘0‘] != 0) {
                nextPosition = hotal[command[1]-‘0‘];
            }
            return true;
    }
}

// 开机
// 描述:开机运行命令，停机后输出命令数
void run() {
    int nowPosition = 0;
    int nextPosition;

    runedCommandNum = 0;
    while (runCommandAt(nowPosition, nextPosition)) {
        //printf("nextPosition = %d, command = %03d\n", nextPosition, memory[nextPosition]);
        nowPosition = nextPosition;
        runedCommandNum++;
    }
    runedCommandNum++;
    printf("%d\n", runedCommandNum);
}

int main() {
    //int t;
    //scanf("%d", &t);
    //scanf("%*[ \n]");
    //while (t--) {
    //    memset(memory, 0, sizeof(memory));
    //    memset(hotal, 0, sizeof(hotal));
    //    int nowPosition = 0;
    //    while(readIntInThisLine(nowPosition) == true) nowPosition++;
    //    run();
    //}
    int n;
    memset(memory, 0, sizeof(memory));
    memset(hotal, 0, sizeof(hotal));
    int now = 0;
    while (scanf("%d", &n) != EOF) {
        memory[now++] = n%1000;
    }
    run();
    return 0;
}