Question in polish Notation example infix notation 15841 po

Question in polish Notation. example:

infix notation : (1+5)*(8-(4-1))

postix notation : 15+841--*

Given a consant string

: 1. Write just the function in C and the whole program in MIPS assembly that converts with the help of stack, the given string and makes it postfix. Then write another function in C and then the program in MIPS assembly that calculates the result of the converted(postix) function.

Solution

The function to convert infix to postfix in C.

int infixToPostfix(char* exp)
{
int i, k;
struct Stack* stack = createStack(strlen(exp));
if(!stack)
return -1 ;

for (i = 0, k = -1; exp[i]; ++i)
{
if (isOperand(exp[i]))
exp[++k] = exp[i];
else if (exp[i] == \'(\')
push(stack, exp[i]);
else if (exp[i] == \')\')
{
while (!isEmpty(stack) && peek(stack) != \'(\')
exp[++k] = pop(stack);
if (!isEmpty(stack) && peek(stack) != \'(\')
return -1;
else
pop(stack);
}
else
{
while (!isEmpty(stack) && Prec(exp[i]) <= Prec(peek(stack)))
exp[++k] = pop(stack);
push(stack, exp[i]);
}
}
while (!isEmpty(stack))
exp[++k] = pop(stack );
exp[++k] = \'\\0\';
printf( \"%s\ \", exp );
}

C program to evaluate postfix expression,with Push and Pop with their usual meanings

void EvalPostfix()
{
char pofx[50],ch;
int i=0,op1,op2;
printf(\"\ \ Enter Postfix Expression : \");
scanf(\"%s\",pofx);
while( (ch=pofx[i++]) != \'\\0\')
{
if(isdigit(ch)) push(ch-\'0\');
else
{
op2=pop();
op1=pop();
switch(ch)
{
case \'+\':push(op1+op2);break;
case \'-\':push(op1-op2);break;
case \'*\':push(op1*op2);break;
case \'/\':push(op1/op2);break;
}
}
}
printf(\"\ Given Postfix Expression: %s\ \",pofx);
printf(\"\ Result after Evaluation: %d\ \",s[top]);
}

The exact program in MIPS for Postfix Evaluation would look like below