Token Instruction::eval(const std::string& expression)
{
// 1. Split string into a token list
tokenization(expression);
// 2. Convert tokens from infix notation to postfix notation
infix_to_postfix();
// 3. Eval postfixed expression
return eval_postfix();
}
int truth_table(char ipstr[], int fnvalues[], int *no_of_variables){
int i, j, output, len;
remove_spaces(ipstr);
if(check_for_valid_characters(ipstr)){
printf("ERROR! Use only valid characters - ~&|() a-z A-Z\n");
return 1;
}
set_precedence(precedence, ipstr);
get_variables(listvar, &numvar, precedence);
if(conv_to_postfix(ipstr, opstr, precedence) == 1){
printf("\nError in input\n");
return 1;
}
len = strlen(ipstr);
/* Truth-table Printing */
printf("\n");
for(i=0; i<numvar; i++){
printf("%c ", listvar[i]);
}
printf("%s ", ipstr);
for(i=0; i<(1<<numvar); i++){
/* For each permutation of bits */
printf("\n");
compute_val_var_from_perm(i, valvar, numvar);
for(j=0; j<numvar; j++)
printf("%d ", valvar[j]);
output = eval_postfix(opstr, valvar, numvar, listvar);
if(output == 1){
printf("Error : eval - not enuff operands\n");
return 1;
}
fnvalues[i] = output - '0';
printf("%*c ", len/2 + 1, output);
}
*no_of_variables = numvar;
printf("\n");
return 0;
}
int main()
{
char *exp = "231*+9-";
printf("Postfix exp: %s is evaluated to %d\n", exp, eval_postfix(exp));
return 0;
}
/**
This Compares the given expression value to the the value current log , Whether it's conforming that expression or not.
*/
boolean isValideLog(char *expression)
{
int i=0,j,k=0,key=1;
j=0;
char compchar='\0';
char newstr[N],keystr[N],valuestr[N];
while(expression[i]!='\0')
{
if(expression[i]==' ')
{
i++;
continue;
}
else if(expression[i]=='='||expression[i]=='>'||expression[i]=='<')
{
compchar=expression[i];
keystr[j]='\0';
key=0;
j=0;
}
else if(expression[i]=='&'||expression[i]=='|'||expression[i]=='!'||expression[i]=='('||expression[i]==')'
||expression[i]=='!')
{
if(expression[i]=='('||expression[i]=='!')
{
newstr[k++]=expression[i];
}
else if((i-1)>=0&&(expression[i]!=')'||expression[i]==')')&&expression[i-1]==')')
{
newstr[k++]=expression[i];
}
else{
valuestr[j]='\0';
Tries *node;
node=find(&root,keystr);
if(node==NULL)
{
newstr[k++]='0';
}
else if(!strcmp(keystr,s[1]))
{
int t=0;
switch(compchar)
{
case '=':
if(atoi(node->value)==atoi(valuestr))
t=1;
break;
case '<':if(atoi(node->value)<atoi(valuestr))
t=1;
break;
case '>': if(atoi(node->value)>atoi(valuestr))
t=1;
}
if(t==1)
newstr[k++]='1';
else
newstr[k++]='0';
}
else if(!strcmp(keystr,s[2]))
{
int t=0;
switch(compchar)
{
case '=':
if(atoi(node->value)==atoi(valuestr))
t=1;
break;
case '<':if(atoi(node->value)<atoi(valuestr))
t=1;
break;
case '>': if(atoi(node->value)>atoi(valuestr))
t=1;
}
if(t==1)
newstr[k++]='1';
else
newstr[k++]='0';
}
else if(strcmp(node->value,valuestr))
{
newstr[k++]='0';
}
else
{
newstr[k++]='1' ;
}
newstr[k++]=expression[i];
keystr[0]=valuestr[0]='\0';
key=1;
j=0;
}
}
else
{
if(key==1)
{
keystr[j++]=expression[i];
}
else
{
valuestr[j++]=expression[i];
}
}
i++;
}
if(keystr[0]!='\0'&&valuestr[0]!='\0')
{
valuestr[j]='\0';
Tries *node;
node=find(&root,keystr);
if(node==NULL)
newstr[k++]='0';
else if(!strcmp(keystr,s[1]))
{
int t=0;
if(node){
switch(compchar)
{
case '=':
if(atoi(node->value)==atoi(valuestr))
t=1;
break;
case '<':if(atoi(node->value)<atoi(valuestr))
t=1;
break;
case '>': if(atoi(node->value)>atoi(valuestr))
t=1;
}
}
if(t==1)
newstr[k++]='1';
else
newstr[k++]='0';
}
else if(!strcmp(keystr,s[2]))
{
int t=0;
if(node){
switch(compchar)
{
case '=':
if(atoi(node->value)==atoi(valuestr))
t=1;
break;
case '<':if(atoi(node->value)<atoi(valuestr))
t=1;
break;
case '>': if(atoi(node->value)>atoi(valuestr))
t=1;
}
}
if(t==1)
newstr[k++]='1';
else
newstr[k++]='0';
}
else if(strcmp(node->value,valuestr))
{
newstr[k++]='0';
}
else
{
newstr[k++]='1' ;
}
newstr[k++]=expression[i];
keystr[0]=valuestr[0]='\0';
key=1;
j=0;
}
newstr[k]='\0';
char postfix[N];
infix_to_postfix(newstr,postfix);
if(eval_postfix(postfix))
{
return 1;
}
else
return 0;
}