Do while loop in C / C++ with examples
In last tutorial, we discussed for loop in C / C++ with examples and while loop in C / C++ with examples. In this tutorial. We will learn about the C / C++ do while
loop and its working with the help of some examples.
Top 15 do while loop in C / C++ with examples
Here, we will give 10 examples of do while loop in C/C++. These examples are written in two different languages, C and C++.
Example 1: Printing numbers from 1 to 100 with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int i = 1; cout<<"Numbers from 1 to 100:\n "; do{ cout << i << " "; i++; } while (i <= 100); cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> int main(void) { int i = 1; printf("Numbers from 1 to 100: \n"); do{ printf("%d ", i); i++; } while (i <= 100); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 2: Displaying a text 10 times with for do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int i = 1; cout<<"Displaying a text 10 times with do while loop in C / C++. \n\n"; do{ cout <<"Hello, I'm learnc.net\n"; i++; } while (i <= 10); cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> int main(void) { int i = 1; printf("Displaying a text 10 times with do while loop in C / C++. \n\n"); do{ printf("Hello, I'm learnc.net\n"); i++; } while (i <= 10); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 3: Find the sum of first n Natural Numbers with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int num, sum, i = 1; sum = 0; cout << "Enter a positive integer: "; cin >> num; do{ sum += i; i++; } while(i <= num); cout << "Sum = " << sum << endl; cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> int main(void) { int num, sum, i = 1, j = 1; sum = 0; printf("Enter a positive integer: "); scanf("%d", &num); printf("Numbers from 1 to %d: ",num); do{ printf("%d ", j); j++; } while (j <= num); do{ sum += i; i++; } while (i <= num); printf("\nSum = %d\n", sum); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 4: Display elements of array using do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int arr[]={19, 2, 17, 1, 2000, 2003}; int i = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ cout<<"Elements of array: "; do{ cout<<arr[i]<<" "; i++; } while(i<6); cout<<"\n\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> int main(void) { int arr[]={19, 2, 17, 1, 2000, 2003}; int i = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ printf("Elements of array: "); do{ printf("%d ",arr[i]); i++; } while(i<6); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 5: Displaying even numbers from 1 to n with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int n, i = 1; cout<<"Enter number n: "; cin>>n; cout<<"Even numbers from 1 to "<< n<<" is: \n"; do{ if(i % 2 == 0) cout<<i<<" "; i++; } while(i <= n); cout<<"\n\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int n, i = 1; printf("Enter number n: "); scanf("%d", &n); printf("Even numbers from 1 to %d is: ", n); do{ if(i % 2 == 0) printf("%d ", i); i++; } while(i <= n); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 6: Displaying odd numbers from 1 to n with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int n, i = 1; cout<<"Enter number n: "; cin>>n; cout<<"Odd numbers from 1 to "<< n<<" is: \n"; do{ if(i % 2 == 1) cout<<i<<" "; i++; } while(i <= n); cout<<"\n\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int n, i = 1; printf("Enter number n: "); scanf("%d", &n); printf("Odd numbers from 1 to %d is: ", n); do{ if(i % 2 == 1) printf("%d ", i); i++; } while(i <= n); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 7: Displaying primes from 1 to n with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; bool isPrimes(int n) { if (n < 2){ return false; } if (n == 2){ return true; } if (n % 2 == 0){ return false; } for (int i = 3; i < (n - 1); i += 2){ if (n % i == 0){ return false; } } return true; } int main() { int n, i = 1; cout<<"Enter number n: "; cin>>n; cout<<"Primes from 1 to "<< n<<" is: \n"; do{ if(isPrimes(i)) cout<<i<<" "; i++; } while(i <= n); cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> bool isPrimes(int n) { if (n < 2){ return false; } if (n == 2){ return true; } if (n % 2 == 0){ return false; } for (int i = 3; i < (n - 1); i += 2){ if (n % i == 0){ return false; } } return true; } int main(void) { int n, i = 1; printf("Enter number n: "); scanf("%d", &n); printf("Primes from 1 to %d is: ", n); do{ if(isPrimes(i)) printf("%d ", i); i++; } while(i <= n); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 8: Displaying even numbers in array with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; int i = 0, j = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ cout<<"Elements of array: "; do{ cout<<arr[i]<<" "; i++; } while(i<9); cout<<"\nEven numbers in array: "; do{ if(arr[j] % 2 == 0) cout<<arr[j]<<" "; j++; } while(j<9); cout<<"\n\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; int i = 0, j = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ printf("Elements of array: "); do{ printf("%d ",arr[i]); i++; } while(i<9); printf("\nEven numbers in array: "); do{ if(arr[j] % 2 == 0) printf("%d ",arr[j]); j++; } while(j<9); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 9: Displaying odd numbers in array with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; int i = 0, j = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ cout<<"Elements of array: "; do{ cout<<arr[i]<<" "; i++; } while(i<9); cout<<"\nOdd numbers in array: "; do{ if(arr[j] % 2 == 1) cout<<arr[j]<<" "; j++; } while(j<9); cout<<"\n\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; int i = 0, j = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ printf("Elements of array: "); do{ printf("%d ",arr[i]); i++; } while(i<9); printf("\nOdd numbers in array: "); do{ if(arr[j] % 2 == 1) printf("%d ",arr[j]); j++; } while(j<9); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 10: Displaying primes numbers in array with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; bool isPrimes(int n) { if (n < 2){ return false; } if (n == 2){ return true; } if (n % 2 == 0){ return false; } for (int i = 3; i < (n - 1); i += 2){ if (n % i == 0){ return false; } } return true; } int main() { int arr[]={1, 5, 9, 7, 11}; int i = 0, j = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ cout<<"Elements of array: "; do{ cout<<arr[i]<<" "; i++; } while(i<5); cout<<"\nPrimes in array: "; do{ if(isPrimes(arr[j])) cout<<arr[j]<<" "; j++; } while(j<5); cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> bool isPrimes(int n) { if (n < 2){ return false; } if (n == 2){ return true; } if (n % 2 == 0){ return false; } for (int i = 3; i < (n - 1); i += 2){ if (n % i == 0){ return false; } } return true; } int main(void) { int arr[]={1, 5, 9, 7, 11}; int i = 0, j = 0; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ printf("Elements of array: "); do{ printf("%d ",arr[i]); i++; } while(i<5); printf("\nPrimes in array: "); do{ if(isPrimes(arr[j])) printf("%d ",arr[j]); j++; } while(j<5); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 11: Find the sum of elements in array with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int sum = 0, i = 0, j = 0; int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ cout<<"Elements of array: "; do{ cout<<arr[i]<<" "; i++; } while(i<9); do{ sum += arr[j]; j++; } while(j<9); cout<<"\nSum of elements in array: "<<sum; cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int sum = 0, i = 0, j = 0; int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ printf("Elements of array: "); do{ printf("%d ",arr[i]); i++; } while(i<9); do{ sum += arr[j]; j++; } while(j<9); printf("\nSum of elements in array: %d",sum); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 12: Find the sum of even elements in array with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int sum = 0, i = 0, j = 0;; int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ cout<<"Elements of array: "; do{ cout<<arr[i]<<" "; i++; } while(i<9); do{ if(arr[j] % 2 == 0) sum += arr[j]; j++; } while(j<9); cout<<"\nSum of even elements in array: "<<sum; cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int sum = 0, i = 0, j = 0; int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ printf("Elements of array: "); do{ printf("%d ",arr[i]); i++; } while(i<9); do{ if(arr[j] % 2 == 0) sum += arr[j]; j++; } while(j<9); printf("\nSum of even elements in array: %d",sum); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 13: Find the sum of odd elements in array with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int sum = 0, i = 0, j = 0;; int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ cout<<"Elements of array: "; do{ cout<<arr[i]<<" "; i++; } while(i<9); do{ if(arr[j] % 2 == 1) sum += arr[j]; j++; } while(j<9); cout<<"\nSum of odd elements in array: "<<sum; cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int sum = 0, i = 0, j = 0; int arr[]={1, 5, 9, 7, 11, 2, 10, 6, 7}; /* We have set the value of variable i * to 0 as the array index starts with 0 * which means the first element of array * starts with zero index. */ printf("Elements of array: "); do{ printf("%d ",arr[i]); i++; } while(i<9); do{ if(arr[j] % 2 == 1) sum += arr[j]; j++; } while(j<9); printf("\nSum of odd elements in array: %d",sum); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 14: Dislaying the multiplication table with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int n, i = 1; cout<<"Enter number n: "; cin>>n; do{ cout<<n<<" x " <<i<<" = "<<n*i<<"\n"; i++; } while(i<= 9); cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> #include <stdbool.h> int main(void) { int n, i = 0; printf("Enter number n: "); scanf("%d", &n); do{ printf("%d x %d = %d\n",n,i,n*i); i++; } while(i<= 9); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output:
Example 15: Display a menu with do while loop in C / C++
C++ programming:
#include <iostream> using namespace std; int main() { int selection; do { cout << "\n------------Menu------------- \n"; cout << "1) Withdraw money\n"; cout << "2) Transfers\n"; cout << "3) Recharge\n"; cout << "4) Check account\n"; cout << "Your choice is: "; cin >> selection; if(selection < 1 || selection > 4) cout<<"\nYou can only choose from 1 to 4, please choose again!\n"; } while (selection < 1 || selection > 4); cout << "You have selected option: #" << selection << "\n"; cout<<"\n-------------------------------\n"; cout<<"This program is posted at learnnc.com"; return 0; }
C programming:
#include <stdio.h> int main(void) { int selection; do { printf("\n------------Menu------------- \n"); printf("1) Withdraw money\n"); printf("2) Transfers\n"); printf("3) Recharge\n"); printf("4) Check account\n"); printf("Your choice is: "); scanf("%d", &selection); if(selection < 1 || selection > 4) printf("\nYou can only choose from 1 to 4, please choose again!\n"); } while (selection < 1 || selection > 4); printf("You have selected option: #%d\n",selection); printf("\n-------------------------------\n"); printf("This program is posted at learnnc.com"); return 0; }
Output: