emitter.c

把中缀表达式转换为后缀表达式并计算结果~~第一个编译试验作业~

/*******************    emitter.c    **********************************************/
#include "global.h"
emit(t,tval)//生成输出
  int t,tval;
  
{

   switch(t){
    case'+':  a[i-2]=a[i-2]+a[i-1];i=i-1; printf("%c\n",t);
		        printf("这一步计算结果为：");printf("\n%d\n",a[0]);break;
	case'-':  a[i-2]=a[i-2]-a[i-1];i=i-1; printf("%c\n",t);
	        	printf("这一步计算结果为：");printf("\n%d\n",a[0]);break;
	case'*':  a[i-2]=a[i-2]*a[i-1];i=i-1; printf("%c\n",t);
	        	printf("这一步计算结果为：");printf("\n%d\n",a[0]);break;
	case'/':  a[i-2]=a[i-2]/a[i-1];i=i-1; printf("%c\n",t);
		        printf("这一步计算结果为：");printf("\n%d\n",a[0]);break;
    case DIV:
		printf("DIV\n");break;
    case MOD:
		printf("MOD\n");break;
	case NUM:
		a[i] = tval;
		i = i+1;
		printf("%d\n",tval);break;
	case ID:
		printf("%s\n",symtable[tval].lexptr);break;
	default:
		printf("token %d,tokenval %d\n",t,tval);
   }
}