/* BFS(breadth-first search) and DFS(depth-first search)*/#include<stdio.h>
#include<stdlib.h>
int q[20],top=-1,front=-1,rear=-1,a[20][20],vis[20],stack[20];
int delete();
void add(int item);
void bfs(int s,int n);
void dfs(int s,int n);
void push(int item);
int pop();

void main()
{
int n,i,s,ch,j;
char c,dummy;
printf(“ENTER THE NUMBER VERTICES “);
scanf(“%d”,&n);
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
printf(“ENTER 1 IF %d HAS A NODE WITH %d ELSE 0 “,i,j);
scanf(“%d”,&a[i][j]);
}
}
printf(“THE ADJACENCY MATRIX IS\n”);
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
printf(” %d”,a[i][j]);
}
printf(“\n”);
}

do
{
for(i=1;i<=n;i++)
vis[i]=0;
printf(“\nMENU”);
printf(“\n1.B.F.S”);
printf(“\n2.D.F.S”);
printf(“\nENTER YOUR CHOICE”);
scanf(“%d”,&ch);
printf(“ENTER THE SOURCE VERTEX :”);
scanf(“%d”,&s);

switch(ch)
{
case 1:bfs(s,n);
break;
case 2:
dfs(s,n);
break;
}
printf(“DO U WANT TO CONTINUE(Y/N) ? “);
scanf(“%c”,&dummy);
scanf(“%c”,&c);
}while((c==’y’)||(c==’Y’));
}//main exit

void bfs(int s,int n)
{
int p,i;
add(s);
vis[s]=1;
p=delete();
if(p!=0)
printf(” %d”,p);
while(p!=0)
{
for(i=1;i<=n;i++)
if((a[p][i]!=0)&&(vis[i]==0))
{
add(i);
vis[i]=1;
}
p=delete();
if(p!=0)
printf(” %d “,p);
}
for(i=1;i<=n;i++)
if(vis[i]==0)
bfs(i,n);
}

void add(int item)
{
if(rear==19)
printf(“QUEUE FULL”);
else
{
if(rear==-1)
{
q[++rear]=item;
front++;
}
else
q[++rear]=item;
}
}
int delete()
{
int k;
if((front>rear)||(front==-1))
return(0);
else
{
k=q[front++];
return(k);
}
}

void dfs(int s,int n)
{
int i,k;
push(s);
vis[s]=1;
k=pop();
if(k!=0)
printf(” %d “,k);
while(k!=0)
{
for(i=1;i<=n;i++)
if((a[k][i]!=0)&&(vis[i]==0))
{
push(i);
vis[i]=1;
}
k=pop();
if(k!=0)
printf(” %d “,k);
}
for(i=1;i<=n;i++)
if(vis[i]==0)
dfs(i,n);
}

void push(int item)
{
if(top==19)
printf(“Stack overflow “);
else
stack[++top]=item;
}

int pop()
{
int k;
if(top==-1)
return(0);
else
{
k=stack[top–];
return(k);
}
}

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
}