An algorithm for converting infix expressions to postfix expressions

1, from the left and right to the arithmetic expression scan, each read into a character s1[i];

2, if the number or decimal point encountered, then immediately write S2[i], if the arithmetic operator, "" (space) written to s2[i];

3, encountered the left parenthesis "(" then pressure stack;

4, if the arithmetic operators, if their priority than the top element of the stack, then directly into the stack, or pop-up stack top element output to S2[i], until the top element of the new stack is lower priority, and then press the stack;

5, if the right parenthesis ")", then the top element of the stack output to s2[i] until the top of the stack is "(", and then cancel each other; when the "#" symbol is scanned, the expression string is fully entered, all the operators in the stack are output to s2[i], and the top element of the stack is removed.

1 intIs_op (Charop)2  {3    Switch(OP)4{ Case '+':5      Case '-':6      Case '*':7      Case '/':return 1;8     default:return 0;9     }Ten  } One /****************************/ A /*to determine the precedence of an operator*/ - /****************************/ - intPriorityCharop) the    { -      Switch(OP) -        { -            Case '(':return 0; +            Case '+': -            Case '-':return 1; +            Case '*': A            Case '/':return 2; at         default:return-1; -         } -   } -  - /*********************************/ - /*infix expression, converted to postfix expression*/ in /*********************************/ - voidPostfixCharE[],Charf[]) to {seqstack opst; +   inti,j; -Initstack (&opst); thePush (&opst,' /'); *i=j=0; $    while(e[i]!=' /')Panax Notoginseng{if((e[i]>='0'&& e[i]<='9') || e[i]=='.') -F[j++]=e[i];/*Digital*/ the       Else if(e[i]=='(')/*opening parenthesis*/ +Push (&opst,e[i]); A            Else if(e[i]==')')/*closing parenthesis*/ the{ while(Stacktop (&opst)! ='(') +F[j++]=pop (&opst); -Pop (&AMP;OPST);/*' (' Out of the stack*/ $                } $            Else if(Is_op (E[i]))/*' +,-, *,/'*/ -{f[j++]=' ';/*two operands separated by a space*/ -                     while(Priority (Stacktop (&AMP;OPST)) >=Priority (E[i])) theF[j++]=pop (&opst); - WuyiPush (&opst,e[i]);/*current meta-stack*/ the                    } -i++;/*deal with the next dollar*/ Wu     } -  About      while(!stackempty (&opst)) $F[j++]=pop (&opst); -f[j]=' /'; -}

An algorithm for converting infix expressions to postfix expressions