10 simple c++ programs for beginners

C++ is one the most popular languages in the programming world. In this article we will be looking towards 10 simple programs for beginners in CPP.

1. Adding to numbers in C++.
   Ans. Take two variables and take user input and add them.

   #include <iostream>
   using namespace std;
   int main() {
   int a ;
   int b ;
   cin>>a>>b;
   cout<<a+b;
   return 0;
   }
   Input: 2 5
   Output: 7

2. Check if a number is even or odd.
   Ans. If the given number is divisible by 2 then it is even otherwise odd.

   #include <iostream>
   using namespace std;
   int main() {
   int a ;
   cin>>a;
   if(a%2 == 0)  // if remainder is zero then even number
       cout<<”even”;
   else       cout<<”odd”;
   return 0;
   }
   Input: 8
   Output: even

3. Write a program to swap two numbers.
   Ans. Use a temporary variable to store one of the numbers.

   #include <iostream>
   using namespace std;
   int main() {
   int a = 10;
   int b = 20;
   cout<<a<<" "<<b<<endl;
   int temp = a;
   a = b;
   b = temp;
   cout<<a<<" "<<b<<endl;
   return 0;
   }
   Output: 10 20
   20 10

4. Write a program to find the largest number among three numbers.
   Ans. A number will be largest if number is greater than both the other numbers.

   #include <iostream>
   using namespace std;
   int main() {
   float a, b, c;
   cin >> a >> b >> c;
   if(a >= b && a >= c)
       cout << "Largest number: " << a;
   if(b >= a && b >= c)
       cout << "Largest number: " << b;
   if(c >= a && c >= b)
       cout << "Largest number: " << c;
   return 0;
   }
   Input: 1 2 3
   Largest number: 3

5. Find the sum of all the natural numbers from 1 to n.
   Ans. We can do this using two ways, one is by iterating from 1 to n and adding them up while the other way is using the summation formula -

   summation of i from 1 to n=n(n+1)/2=1+2+3+4+..+(n-1)+n
   #include <iostream>
   using namespace std;
   int main()
   {
   int n, sum = 0;
   cin >> n;
   for (int i = 1; i <= n; ++i) {
       sum += i;
   }
   // or sum = n*(n+1)/2;
   cout << sum;
   return 0;
   }
   Input: 5
   Output: 15

6. Write a program to check whether a number is prime or not.
   Ans. A prime number is not divisible by any number smaller than it except 1. Basically, it has only two factors 1 and itself.

   #include <iostream>
   using namespace std;
   int main() {
   int a ;
   cin>>a;
   int b = 2;
   //start from b as 1 can divide any number
   bool prime = true;
   while(b!=a){
       if(a%b == 0)
           {
               prime = false;
               break;
           }
       b++;
   }
   if(prime)
   cout<<"prime";
   else cout<<"not prime";
   return 0;
   }
   Output: prime

7. Compute the power a given number to a given power.
   Ans. We need to keep multiplying the same number power times.

   3^3=3*3*3=27
   #include <iostream>
   using namespace std;
   int main() 
   {
   int power;
   float base, result = 1;
   cin >> base >>power;
   while (power != 0) {
       result *= base;
       power--;
   }
   cout << result;
   return 0;
   }
   Input: 3 3
   Output: 27

8. Calculate the average of all the elements present in an array.
   Ans.

   average= summation〖arr[i]〗/n
   #include <iostream>
   using namespace std;
   int main()
   {
   int n;
   cin>>n;
   int arr[n];
   float sum = 0.0;
   for(int i = 0;i<n;i++)
       cin>>arr[i];
   for(int i = 0;i<n;i++)
       sum += arr[i];
   cout<<(float)(sum/(float)n);
   return 0;
   }
   Input: 3
   1 4 5
   Output: 3.33333

9. Write a program to find the GCD of two numbers.
   Ans. GCD is the greatest common divisor of the two numbers.

   #include <iostream>
   using namespace std;
   int gcd(int a,int b){
   if(b == 0)
       return a;
   return gcd(b,a%b);
   }
   int main() {
   int a ,b ;
   cin>>a>>b;
   cout<<gcd(a,b);
   return 0;
   }
   Input: 35 25
   Output: 5

10. Write a function to find the length of a string in CPP.
    Ans. Iterate through the string and increase count by 1 till we reach the end of the string.

    #include <iostream>
    using namespace std;
    int main() 
    {
    string str;
    cin>>str;
    int count = 0;
    for(int i = 0;str[i];i++) // till the string character is null
        count++;
    cout<<count;
    }
    Input: abcde
    Output: 5

This article tried to discuss Simple C++ programs for beginners. Hope this blog helps you understand the concept. To practice more problems you can check out MYCODE | Competitive Programming.