plzzz help…….it doesn’t evaluate right……!

[WeldonGarrison]

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#include <stdio.h> #include <ctype.h>   #define MAX 50 #define EMPTY -1   struct stack { int data[MAX]; int top; };   int isempty(struct stack *s) { return (s->top == EMPTY) ? 1 : 0; }   void emptystack(struct stack* s) { s->top = EMPTY; }   void push(struct stack* s,int item) { if(s->top == (MAX-1)) { printf("nSTACK FULL"); } else { ++s->top; s->data[s->top]=item; } }   int pop(struct stack* s) { int ret=EMPTY; if(s->top == EMPTY) printf("nSTACK EMPTY"); else { ret= s->data[s->top]; --s->top; } return ret; }   void display(struct stack s) { while(s.top != EMPTY) { printf("n%d",s.data[s.top]); s.top--; } }   int isoperator(char e) { if(e == '+' || e == '-' || e == '*' || e == '/' || e == '%') return 1; else return 0; }   int priority(char e) { int pri = 0;   if(e == '*' || e == '/' || e =='%') pri = 2; else { if(e == '+' || e == '-') pri = 1; } return pri; }   int evaluate(char *postfix) { char *p; struct stack stk; int op1,op2,result;   emptystack(&stk); p = &postfix[0];   while(*p != '') { /* removes tabs and spaces */ while(*p == ' ' || *p == 't') { p++; } /* if is digit */ if(isdigit(*p)) { push(&stk,*p - 48); } else { /* it is an operator */ op2 = pop(&stk); op1 = pop(&stk);   switch(*p) { case '+': result = op1 + op2; break;   case '-': result = op1 - op2; break;   case '/': result = op1 / op2; break;   case '*': result = op1 * op2; break;   case '%': result = op1 % op2; break;   default: printf("nInvalid Operator"); return 0; } push(&stk,result); } p++; } result = pop(&stk); return result; }   void infix2postfix(char* infix, char * postfix, int insertspace) { char *i,*p; struct stack X; char n1; emptystack(&X); i = &infix[0]; p = &postfix[0];   while(*i) { while(*i == ' ' || *i == 't') { i++; }   if( isdigit(*i) || isalpha(*i) ) { while( isdigit(*i) || isalpha(*i)) { *p = *i; p++; i++; } /*SPACE CODE*/ if(insertspace) { *p = ' '; p++; } /*END SPACE CODE*/ }   if( *i == '(' ) { push(&X,*i); i++; }   if( *i == ')') { n1 = pop(&X); while( n1 != '(' ) { *p = n1; p++; /*SPACE CODE*/ if(insertspace) { *p = ' '; p++; } /*END SPACE CODE*/ n1 = pop(&X); } i++; }   if( isoperator(*i) ) { if(isempty(&X)) push(&X,*i); else { n1 = pop(&X); while(priority(n1) >= priority(*i)) { *p = n1; p++; /*SPACE CODE*/ if(insertspace) { *p = ' '; p++; } /*END SPACE CODE*/ n1 = pop(&X); } push(&X,n1); push(&X,*i); } i++; } } while(!isempty(&X)) { n1 = pop(&X); *p = n1; p++; /*SPACE CODE*/ if(insertspace) { *p = ' '; p++; } /*END SPACE CODE*/ } *p = ''; }   int main(void) { char infix[MAX], postfix[MAX], result[MAX]; printf("Enter expression: "); fflush(stdin); gets(infix); infix2postfix(&infix[0],&postfix[0],1); printf("nPostfix expression is: %s",&postfix[0]); result[0]=postfix[0]; printf("n %s = %d.",&infix[0],evaluate(&result[0])); return 0; }

• This topic was modified 1 year, 5 months ago by M. Saqib.
• This topic was modified 1 year, 5 months ago by M. Saqib.

[GWILouisaxwzkla]

Heres a postfix to infix program I have on my drive ( hope this helps….. ):

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#include < conio.h ><br /> #include < math.h ><br /> #include < string.h ><br /> #include < stdlib.h ><br /> #include < stdio.h ><br /> <br /> enum Boolean { False = 0 , True = 1 } ;<br /> const int GREATER = 1 ;<br /> const int NOTGREATER = 0 ;<br /> int cnt = 0 , cntcol = 0 , postcnt = 0 ;<br /> <br /> // <hr class="bbcode_rule" /> struct Stack<br /> {<br /> int info ;<br /> Stack * previous;<br /> } * top;<br /> <br /> // <hr class="bbcode_rule" /> void Push ( int number )<br /> {<br /> Stack * current;<br /> current = new ( Stack ) ;<br /> if ( current == 0 )<br /> {<br /> printf ( "n allocation error!!!!! " );<br /> return;<br /> }<br /> current -> info = number ;<br /> current -> previous = top ;<br /> top = current ;<br /> }<br /> <br /> // <hr class="bbcode_rule" /> int Pop ()<br /> {<br /> int temp ;<br /> Stack * current = top;<br /> temp = current -> info ;<br /> top = top -> previous ;<br /> delete current ;<br /> return temp ;<br /> }<br /> <br /> // <hr class="bbcode_rule" /> int StackTop ()<br /> {<br /> return top -> info ;<br /> }<br /> <br /> // <hr class="bbcode_rule" /> Boolean isEmpty()<br /> {<br /> if ( top == NULL )<br /> return True;<br /> else<br /> return False ;<br /> }<br /> <br /> // <hr class="bbcode_rule" /> Boolean isOperand ( char ch )<br /> {<br /> if ( ch >= '0' &#038;& ch <= '9' ) //if is a number<br /> return True;<br /> else<br /> return False ;<br /> }<br /> <br /> // <hr class="bbcode_rule" /> void Infix ( char infix[][10])<br /> {<br /> char c ;<br /> while ( c != 13 )<br /> {<br /> c = getch() ;<br /> putch(c);<br /> if ( c >= '0' &#038;& c <= '9' )<br /> {<br /> infix [cnt][cntcol] = c  ;<br /> cntcol++ ;<br /> }<br /> else if ( c == '+'|| c == '-'|| c == '*'|| c == '/')<br /> {<br /> infix [cnt][cntcol] = '' ;<br /> cnt++ ;<br /> infix [cnt][0] = c ;<br /> infix [cnt][1] = '' ;<br /> cnt++ ;<br /> cntcol = 0 ;<br /> }<br /> else if ( c == 13 )<br /> infix[cnt][cntcol] = '' ;<br /> }<br /> }<br /> <br /> <br /> // <hr class="bbcode_rule" /> int Calculate (int op1, char opr, int op2)<br /> {<br /> int ans ;<br /> switch ( opr )<br /> {<br /> case '+' :  ans = op1 + op2 ; break ;<br /> case '-' :  ans = op1 - op2 ; break ;<br /> case '*' :  ans = op1 * op2 ; break ;<br /> case '/' :  ans = op1 / op2 ; break ;<br /> case '^' :  ans = pow(op1, op2) ;<br /> }<br /> return ans ;<br /> }<br /> // <hr class="bbcode_rule" /> int Evaluate ( char postfix[][10] )<br /> {<br /> for ( int i = 0 ; i <= cnt ; i ++ )<br /> {<br /> char ch = postfix<i>[0] ;<br /> char ch1[10] ;<br /> strcpy ( ch1 ,postfix </i><i> ) ;<br /> //  cout <<endl<< atoi ( ch1) ;<br /> if ( isOperand ( ch ) == True )<br /> Push ( atoi(ch1)  );<br /> else<br /> {<br /> int op2 = Pop () ;<br /> int op1 = Pop () ;<br /> int ans = Calculate ( op1, ch, op2 ) ;<br /> //     cout << ans << endl ;<br /> Push ( ans ) ;<br /> }<br /> }<br /> int ans = Pop () ;<br /> return ans ;<br /> }<br /> <br /> // </i> <hr class="bbcode_rule" /> int CheckP (char cur, char st)<br /> {<br /> int a = NOTGREATER ;<br /> <br /> if ( cur == '(' )<br /> a = GREATER ;<br /> else if ( cur != '(' &#038;& st == '(' )<br /> a = GREATER ;<br /> else if ( cur != '(' &#038;& st != '(' )<br /> {<br /> if ( ( cur == '*' || cur == '/' ) &#038;& ( st == '+' || st == '-' ) )<br /> a = GREATER ;<br /> }<br /> return a ;<br /> <br /> }<br /> <br /> <br /> // <hr class="bbcode_rule" /> void infixToPostfix ( char infix[][10], char postfix[][10] )<br /> {<br /> int postcol = 0 ;<br /> for ( int i = 0 ; i <= cnt ; i ++ )<br /> {<br /> // strcpy(postfix<i>, infix </i><i>) ;<br /> // cout << postfix</i><i> ;<br /> char ch;<br /> ch = infix</i><i>[0]  ;<br /> if ( isOperand ( ch ) == True )<br /> strcpy ( postfix [postcnt++] , infix </i><i> ) ;<br /> else<br /> {<br /> if ( isEmpty() == True )<br /> Push ( int(ch) ) ;<br /> else<br /> {<br /> while ( CheckP( ch, StackTop() ) != GREATER &#038;& isEmpty() != True )<br /> {<br /> char c ;<br /> if ( ch == ')' )<br /> {<br /> do<br /> {<br /> c = char ( Pop() ) ;<br /> if ( c != '(')<br /> {<br /> postfix [postcnt][postcol] = c ;<br /> postfix [postcnt][postcol+1] = '' ;<br /> postcnt++ ;<br /> }<br /> }while ( c != '(' &#038;& isEmpty() != True);<br /> break ;<br /> }<br /> else<br /> c = char ( Pop() ) ;<br /> if ( c != '(' &#038;& c != ')' )<br /> {<br /> postfix [postcnt][postcol] = c ;<br /> postfix [postcnt][postcol+1] = '' ;<br /> postcnt++ ;<br /> }<br /> }<br /> if ( ch != ')' )<br /> Push ( int(ch) ) ;<br /> }<br /> }<br /> }<br /> <br /> while ( isEmpty () != True )<br /> {<br /> char c = char ( Pop () ) ;<br /> postfix [postcnt][postcol] = c ;<br /> postfix [postcnt][postcol+1] = '';<br /> postcnt++ ;<br /> }<br /> //   postfix[postcnt][postcol]  = '';<br /> }<br /> <br /> //</i> <hr class="bbcode_rule" /> void Postfix ( char postfix[][10] )<br /> {<br /> char ch[10] ;<br /> for ( int i = 0; i <= postcnt; i++ )<br /> {<br /> strcpy(ch , postfix<i> ) ;<br /> printf ( "%c" ,ch );<br /> }<br /> }<br /> <br /> // </i> <hr class="bbcode_rule" /> void main()<br /> {<br /> //clrscr();<br /> top = NULL ;<br /> <br /> char infix [ 50 ][ 10 ] ;<br /> char postfix [ 50 ][ 10 ] ;<br /> <br /> //gotoxy ( 5, 8 ) ;<br /> printf ( "Enter Arithematic Expression ...................... : " );<br /> Infix ( infix ) ;<br /> <br /> infixToPostfix ( infix, postfix ) ;<br /> //gotoxy ( 5, 10 ) ;<br /> printf ( "Arithematic Expression in Postfix Notation......... : " );<br /> Postfix ( postfix ) ;<br /> int ans = Evaluate ( postfix ) ;<br /> //gotoxy (5, 11 ) ;<br /> printf (  "The Answer of Expression .......................... : " );<br /> printf ( "%i", ans );<br /> <br /> getch();<br /> }<br /> // <hr class="bbcode_rule" />

[PSBMaira490593]

Hi,
please run it again in new window and check the variable that you have declared are right or not.
thanks.

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Debra Fine

[M. Saqib]

OK

[Author]

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