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Description: In this C++ programming example, 2 files are given. Description of these files is as follows:
fileA It contains code in a
certain language. Format of this file will be:
operation
(space) variable-name (comma) (space) variable/integer
operations:
only the following operations are legal
and
mov
sub
add
operands:
any integer between 0-9
variables: ax, bx, cx, dx
Operands can only be two but variable name should be
first operand, second can be variable name or integer. E.g.
mov cx, dx
is a valid statement, whereas
mov 5, ax
is not
fileB It contains the code
against each keyword or variable name from fileA.
Operation-name (space) code
mov A8
add B8
sub C8
and D8
ax F1
bx F2
cx F3
dx F4
The following C++ language
basic program reads each statement from fileA
and looks for each of its keyword/variable’s equivalent code in fileB and produces an output fileC. For example,
mov bx, 5 will be:
A8F25
However any integer operand read from fileA will be placed as it in your
output file. E.g.
For the statement mov ax, 5 output statement will be A8F15
But before reading from fileA, this C++ code also has
to check file for syntax errors. In case of any syntax error there will be no
conversion.
#include <iostream>
#include <fstream>
using namespace std;
bool CHECK(int&no_of_iterations) //Checks fileA for syntax errors
{
int i=0,j=0;
char
A_line[11],check[4];
ifstream
Ain("fileA.txt");
while (!Ain.eof()){
Ain.getline(A_line,11);
for (j=0;j<3;j++)
check[j]=A_line[j];
check[j]='\0';
if ( strcmp(check,"add") &&
strcmp(check,"mov") && strcmp(check,"and") &&
strcmp(check,"sub") )
//function
break;
if (A_line[j]!=' ') //space
break;
j++;
if ( !(A_line[j]>='a' &&
A_line[j]<='d')&&(A_line[j+1]=='x') ) //ax,bx,cx,dx
break;
j+=2;
if (A_line[j]!=',') //,
break;
j++;
if (A_line[j]!=' ') //space
break;
j++;
if( !((A_line[j]>='0'&&A_line[j]<='9') ||
((A_line[j]>='a' && A_line[j]<='d') && (A_line[j+1]=='x')) ) )
break;
no_of_iterations++;
}
if (!Ain.eof()){
cout<<"Syntax
Error. Conversion not possible"<<endl;
return false;
}
return true;
}
void Ain(char oper[],char var1[],char var2[],int count)
{
ifstream
Ain("fileA.txt");
for (int
a=1;a<=count;a++){
Ain>>oper;
Ain.ignore(1,' ');
Ain.get(var1,3,',');
Ain.ignore(1,' ');
Ain>>var2;
}
}
void Bin(char B[][8],int b_row)
{
ifstream
Bin("fileB.txt");
for (int i=0;i<b_row;i++)
Bin.getline(B[i],7);
}
void OPER(char C[],char oper[],char B_data[][8],int b_row,int &k)
{
int i=0,j=0;
for
(i=0;i<b_row;i++){
for (j=0;oper[j]!='\0';j++)
if(B_data[i][j]!=oper[j])
break;
if (oper[j]=='\0')
for (k=0;k<2;k++)
C[k]=B_data[i][j+1+k];
}
}
void VAR1(char C[],char var1[],char B_data[][8],int b_row,int &k)
{
int i=0,j=0,l=0;
for
(i=0;i<b_row;i++){
for (j=0;var1[j]!='\0';j++)
if
(B_data[i][j]!=var1[j])
break;
if(var1[j]=='\0')
for
(k=2,l=0;k<4;k++,l++)
C[k]=B_data[i][j+1+l];
}
}
void VAR2(char C[],char var2[],char B_data[][8],int b_row,int &k)
{
int i=0,j=0,l=0;
if ( var2[0]>='0' &&
var2[0]<='9' ){
C[k]=var2[0];
k++;
}
else{
for
(i=0;i<b_row;i++){
for (j=0;var2[j]!='\0';j++)
if (B_data[i][j]!=var2[j])
break;
if(var2[j]=='\0')
for (k=4,l=0;k<6;k++,l++)
C[k]=B_data[i][j+1+l];
}
}
}
int main()
{
const int b_row=8,b_col=8;
int
k=0,count=1,no_of_iterations=0;
char
oper[5],var1[4],var2[4],B_data[b_row][b_col],C[7];
if
(CHECK(no_of_iterations)){
Bin(B_data,b_row);
ofstream
Cout("fileC.txt");
for (int a=1;a<=no_of_iterations;a++){
k=0;
Ain(oper,var1,var2,count);
OPER(C,oper,B_data,b_row,k);
VAR1(C,var1,B_data,b_row,k);
VAR2(C,var2,B_data,b_row,k);
count++;
C[k]='\0';
Cout<<C<<endl;
}
}
return 0;
}
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