#include<stdio.h>
#include<stdlib.h>
int mem[100],reg[4],cond[]={0,0,0,0,0,1},opc,op1,op2,pc;
FILE *fp;
char fname[20];

void load()
{
 printf("Enter file name:");
 scanf("%s",fname);

 fp = fopen(fname,"r");
 if(fp==NULL)
 {
  printf("File %s not found.\n",fname);
  exit(1);
 }

 while(fscanf(fp,"%d",&mem[pc])!=-1)
  pc++;

 fclose(fp);
}

void print()
{
 int i;
 for(i=0;i<pc;i++)
  printf("%06d\n",mem[i]);
}

void run()
{
 int i;
 pc = 0;
 while(1)
 {
  opc = mem[pc]/10000;
  op1 = mem[pc]%10000/1000-1;
  op2 = mem[pc]%1000;

  switch(opc)
  {
  case 0: // STOP
   return;
  case 1: // ADD
   reg[op1]+=mem[op2];
   break;
  case 2: // SUB
   reg[op1]-=mem[op2];
   break;
  case 3: // MULT
   reg[op1]*=mem[op2];
   break;
  case 8: // DIV
   reg[op1]/=mem[op2];
   break;
  case 4: // MOVER
   reg[op1]=mem[op2];
   break;
  case 5: // MOVEM
   mem[op2]=reg[op1];
   break;
  case 6: // COMP
   if(reg[op1] < mem[op2])
    cond[0]=1;
   if(reg[op1] <= mem[op2])
    cond[1]=1;
   if(reg[op1] == mem[op2])
    cond[2]=1;
   if(reg[op1] > mem[op2])
    cond[3]=1;
   if(reg[op1] >= mem[op2])
    cond[4]=1;
   break;
  case 7: // BC
   if(cond[op1]==1)
    pc = op2-1;
   
   for(i=0;i<5;i++)
    cond[i]=0;
   break;
  case 9: // READ
   scanf("%d",&mem[op2]);
   break;
  case 10:// PRINT
    printf("%d\n",mem[op2]);
  }
  pc++;
 }
}

int main()
{
 int ch;

 while(1)
 {
  printf("1.Load\n2.Print\n3.Run\n4.Exit\n");
  printf("Enter your choice (1-4):");
  scanf("%d",&ch);

  switch(ch)
  {
  case 1:
   load();
   break;
  case 2:
   print();
   break;
  case 3:
   run();
   break;
  case 4:
   exit(0);
  }
 }

 return 0;
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}