cpp infix to postfix.
//aight bru, lessgo.
// use this exammple->(a-b/c)*(a/k-l) and implent code on paper to get a good idea.
#include<iostream>
#include<stack>
using namespace std;
int prec(char c)
{
if(c=='^') return 3;
else if(c=='*' || c=='/') return 2;
else if(c=='+' || c=='-') return 1;
else
return -1; // for open brackets. coz we have to pop until we find an opening bracket.
}
string infixtopostfix(string s)
{
stack<char>st;
string res="";
for(int i=0;i<s.length();i++)
{
if((s[i]>='a' && s[i]<='z')||(s[i]>='A' && s[i]<='Z')) res=res+s[i];
else if(s[i]=='(') st.push(s[i]);
else if(s[i]==')')
{
while(!st.empty() && st.top()!='(')
{
res=res+st.top();
st.pop();
}
if(!st.empty()) st.pop();
}
else
{
while(!st.empty() && prec(st.top())>prec(s[i]) )
{
res=res+st.top();
st.pop();
}
st.push(s[i]);
}
}
while(!st.empty())
{
res=res+st.top();
st.pop();
}
return res;
}
int main()
{
string s;
cin>>s;
cout<<infixtopostfix(s);
return 0;
}
postfix to infix c program
#include<stdio.h>
int main()
{
char str[100],oprator[100],operant[100];
int i ,opr=-1,op=-1;
printf("enter the string");
scanf("%s",str);
for (i=0;str[i]!=NULL;i++)
{
if(str[i]=='+'||str[i]=='-'||str[i]=='*'||str[i]=='^'||str[i]=='/')
{
(opr)++;
oprator[opr]=str[i];
}
else
{
(op)++;
operant[op]=str[i];
}
}
printf("operator are:\n");
for (i=0;i<=opr;i++)
printf("%c",oprator[i]);
printf("\noperandas are:\n");
for (i=0;i<=op;i++)
printf("%c",operant[i]);
return 0;
}
infix to postfix in c++
#include<iostream>
#include<stack>
using namespace std;
bool isOperator(char c)
{
if(c=='+'||c=='-'||c=='*'||c=='/'||c=='^')
{
return true;
}
else
{
return false;
}
}
int precedence(char c)
{
if(c == '^')
return 3;
else if(c == '*' || c == '/')
return 2;
else if(c == '+' || c == '-')
return 1;
else
return -1;
}
string InfixToPostfix(stack<char> s, string infix)
{
string postfix;
for(int i=0;i<infix.length();i++)
{
if((infix[i] >= 'a' && infix[i] <= 'z')
||(infix[i] >= 'A' && infix[i] <= 'Z'))
{
postfix+=infix[i];
}
else if(infix[i] == '(')
{
s.push(infix[i]);
}
else if(infix[i] == ')')
{
while((s.top()!='(') && (!s.empty()))
{
char temp=s.top();
postfix+=temp;
s.pop();
}
if(s.top()=='(')
{
s.pop();
}
}
else if(isOperator(infix[i]))
{
if(s.empty())
{
s.push(infix[i]);
}
else
{
if(precedence(infix[i])>precedence(s.top()))
{
s.push(infix[i]);
}
else if((precedence(infix[i])==precedence(s.top()))&&(infix[i]=='^'))
{
s.push(infix[i]);
}
else
{
while((!s.empty())&&( precedence(infix[i])<=precedence(s.top())))
{
postfix+=s.top();
s.pop();
}
s.push(infix[i]);
}
}
}
}
while(!s.empty())
{
postfix+=s.top();
s.pop();
}
return postfix;
}
int main()
{
string infix_exp, postfix_exp;
cout<<"Enter a Infix Expression :"<<endl;
cin>>infix_exp;
stack <char> stack;
cout<<"INFIX EXPRESSION: "<<infix_exp<<endl;
postfix_exp = InfixToPostfix(stack, infix_exp);
cout<<endl<<"POSTFIX EXPRESSION: "<<postfix_exp;
return 0;
}Source: simplesnippets.tech