功能较全的表达式求值程序 C代码

int hashtable[MAX_SIGNAL]; int infix[MAX_SIGNAL]; int postfix[MAX_SIGNAL]; int inlength; int postlength; int parentcount; int signalcount; char *getpassword() { char c; int cnt = 0; while( (c = getch())!= '\r') { if(c=='\b') { printf("\b \b"); cnt--; } else { pass[cnt++] = c; putchar(ECHOCHAR); } if (cnt == MAX_PASSWORD) { break; } } putchar('\n'); return pass; } Value_type fac(Value_type x) { Value_type value=1; if(x<0) return INT_MAX; else if(x<1) return 1; else { for(Value_type f=x;f>0;f--) value=value*f; } return value; } int Hash(char *name) { int h=name[0]%MAX_SIZE; while(1) { if(hashtable[h]==-1) break; else if(strcmp(string[hashtable[h]].name ,name)==0) break; else { if(name[1]=='\0') h+=31; else h+=name[1]; h%=MAX_SIZE; } } return abs(h); } void MakeHashTable( ) { int i; for(i=0;i<MAX_SIZE;i++) hashtable[i]=-1; for(i=1;i<=MAX_OPERATION;i++) hashtable[Hash(string[i].name )]=i; } Kind_type Kind(int h) { return (string[h].kind ); } int Priority(int h) { return (string[h].info .pri ); } int Leading( ) { int k; if(inlength<=-1) return 1; else return (k=Kind(infix[inlength]))==LEFT||k==SINGLE||k==BINARY; } void PutToken(int h) { inlength++; infix[inlength]=h; } void PutToken1(int h) { postlength++; postfix[postlength]=h; } int ExtractWord(char str[],int pos,char *word) { int i; char *pw=word; for(i=pos;isalpha(str[i])||isdigit(str[i]);i++) *pw++=tolower(str[i]); *pw='\0'; return i; } int FindWord(char str[],int pos) { int h; char word[MAX_SIGNAL]; pos=ExtractWord(str,pos,word); h=hashtable[Hash(word)]; if(h!=-1) { if(Leading()==1) { if(Kind(h)==BINARY) { for(int i=0;i<28;i++) printf(" "); printf("二元运算符位置不正确!\n"); return -1; } else PutToken(h); } else { if(Kind(h)!=BINARY) { for(int i=0;i<28;i++) printf(" "); printf("应为二元运算符!\n"); return -1; } else PutToken(h); } return pos; } else { for(int i=0;i<28;i++) printf(" "); printf("标识符不正确!\n"); return -1; } } int FindNumber(char str[],int pos) { if(Leading()==0) { for(int i=0;i<28;i++) printf(" "); printf("常数的位置不正确!\n"); return -1; } else { string[++signalcount].kind =OPERAND; string[signalcount].info .val =atof(&str[pos]); strcpy(string[signalcount].name ,"number"); PutToken(signalcount); for(;isdigit(str[pos])||str[pos]=='.';pos++); return pos; } } int FindSymbol(char str[],int pos) { int h,k; char word[MAX_SIGNAL]; word[0]=str[pos]; word[1]='\0'; pos++; if((h=hashtable[Hash(word)])==-1) { for(int i=0;i<28;i++) printf(" "); printf("表达式中存在无法识别的字符!\n"); return -1; } else if(Leading()!=0) { if(Kind(h)==RIGHT) { for(int i=0;i<28;i++) printf(" "); printf("不应当为右括号!\n"); return -1; } else if(Kind(h)!=BINARY) PutToken(h); else { if(strcmp(word,"+")==0); else if(strcmp(word,"-")==0) PutToken(hashtable[Hash("~")]); else { for(int i=0;i<28;i++) printf(" "); printf("二元运算符不正确!\n"); return -1; } } } else { if(Kind(h)==BINARY||Kind(h)==RIGHT) PutToken(h); else { for(int i=0;i<28;i++) printf(" "); printf("二元运算符不正确!\n"); return -1; } } if((k=Kind(h))==LEFT) parentcount++; else if(k==RIGHT) if(--parentcount<0) { for(int i=0;i<28;i++) printf(" "); printf("右括号太多!\n"); return -1; } return pos; } void GetToken(int &h) { inlength++; h=infix[inlength]; } void GetToken1(int &h) { postlength++; h=postfix[postlength]; } void Translate( ) { int St[MAX_STACK]; int top=-1; int h,h1; Kind_type type; postlength=-1; inlength=-1; int endright; do{ GetToken(h); switch(type=Kind(h)) { case OPERAND: PutToken1(h); break; case LEFT: top++; St[top]=h; break; case RIGHT: h=St[top]; top--; while(top>-1&&Kind(h)!=LEFT) { PutToken1(h); h=St[top]; top--; } break; case SINGLE: case BINARY: endright=0; do{ if(top==-1) endright=1; else if(Kind(St[top])==LEFT) endright=1; else if(Priority(St[top])<Priority(h)) endright=1; else if(Priority(St[top])==Priority(h)&&Priority(h)==MAX_PRIORITY) endright=1; else { h1=h; endright=0; h=St[top]; top--; PutToken1(h); h=h1; } }while(endright==0); top++; St[top]=h; break; case END: while(top>-1) { h=St[top]; top--; PutToken1(h); } break; } }while(type!=END); PutToken1(0); } int ProcessExpress(char *instring) { int len,pos; inlength=-1; parentcount=0; signalcount=MAX_OPERATION; len=strlen(instring); instring[len]='\0'; for(pos=0;pos<len;) { if(instring[pos]==' ') pos++; else if(isalpha(instring[pos])) pos=FindWord(instring,pos); else if(isdigit(instring[pos])||instring[pos]=='.') pos=FindNumber(instring,pos); else pos=FindSymbol(instring,pos); if(pos==-1) return 0; } if(parentcount!=0) { for(int i=0;i<28;i++) printf(" "); printf("括号不匹配!\n"); } PutToken(0); return 1; } void DispInfix( ) { int i; for(i=0;i<20;i++) printf(" "); for(i=0;i<=inlength;i++) { if(strcmp(string[infix[i]].name ,"number")==0) printf(" %g",string[infix[i]].info .val ); else printf(" %s",string[infix[i]].name ); }//变换前 printf("\n"); for(i=0;i<20;i++) printf(" "); for(i=0;i<=inlength;i++) printf(" %d",infix[i]); printf("\n");//变换后 } void DispPostfix() { int i; for(i=0;i<20;i++) printf(" "); for(i=0;i<=postlength;i++) { if(strcmp(string[postfix[i]].name ,"number")==0) printf(" %g",string[postfix[i]].info .val ); else printf(" %s",string[postfix[i]].name ); }//变换前 printf("\n"); for(i=0;i<20;i++) printf(" "); for(i=0;i<=postlength;i++) printf(" %d",postfix[i]); printf("\n");//变换后 } Value_type DoBinary(int h,Value_type x,Value_type y) { switch(h) { case 21: return (x+y); break; case 22: return (x-y); break; case 23: return (x*y); break; case 24: if(y!=(Value_type)0) return (x/y); else return INT_MAX; break; case 25: if(y!=(Value_type)0) return (fmod(x,y)); else return INT_MAX; break; case 26: return (pow(x,y)); break; default: return INT_MAX; break; } } Value_type DoUnary(int h,Value_type x) { switch(h) { case 3: return (-x); break; case 4: return (fabs(x)); break; case 5: if(x>=0) return (sqrt(x)); else return INT_MAX; break; case 6: return (exp(x)); break; case 7: if(x>0) return (log(x)); else return INT_MAX; break; case 8: if(x>0) return (log10(x)); else return INT_MAX; break; case 9: return (sin(x)); break; case 10: return (cos(x)); break; case 11: if(cos(x)==0) return INT_MAX; else return (sin(x)/cos(x)); break; case 12: if(sin(x)==0) return INT_MAX; else return (cos(x)/sin(x)); break; case 13: if(x>1||x<-1) return INT_MAX; else return (asin(x)); break; case 14: if(x>1||x<-1) return INT_MAX; else return (acos(x)); break; case 15: return (atan(x)); break; case 16: return (sinh(x)); break; case 17: return (cosh(x)); break; case 18: return (tanh(x)); break; case 19: if(sinh(x)==0) return INT_MAX; else