- C++ Programming Examples
- C++ Programming Examples
- C++ Hello World
- C++ Get Input
- C++ Print Integer
- C++ Add Two Numbers
- C++ Add Sub Mul Div
- C++ Add Digits
- C++ Find Average Perc
- C++ Find Arithmetic Mean
- C++ Sum of n Natural Numbers
- C++ Sum of n Numbers
- C++ Area Perimeter of Square
- C++ Area Perimeter of Rectangle
- C++ Area Perimeter of Triangle
- C++ Area Circum of Circle
- C++ Find Simple Interest
- C++ Fahrenheit to Celsius
- C++ Celsius to Fahrenheit
- C++ Print Prime Numbers
- C++ Reverse a Number
- C++ Swap Two Numbers
- C++ Print Multiplication Table
- C++ Find Factorial of Number
- C++ Find Factors of Number
- C++ Find HCF & LCM
- C++ Make Calculator
- C++ Count Digits in Number
- C++ Sum of First & Last Digit
- C++ Product of Digits of Number
- C++ Sum of Squares of Digits
- C++ Interchange Digits of Number
- C++ if else Programs
- C++ Check Even or Odd
- C++ Check Prime or Not
- C++ Check Alphabet or Not
- C++ Check Vowel or Not
- C++ Check Leap Year or Not
- Check Reverse equal Original
- C++ Check Perfect Number
- C++ Check Palindrome or Not
- C++ Check Armstrong or Not
- C++ Divisibility Test
- C++ Find Wage of Labor
- C++ Find Discounted Price
- C++ Find Shipping Charge
- C++ Find Telephone Bills
- C++ Calculate Student Grade
- C++ Largest of Two Numbers
- C++ Largest of Three Numbers
- C++ Number Conversion
- C++ Decimal to Binary
- C++ Decimal to Octal
- C++ Decimal to Hexadecimal
- C++ Binary to Decimal
- C++ Binary to Octal
- C++ Binary to Hexadecimal
- C++ Octal to Decimal
- C++ Octal to Binary
- C++ Octal to Hexadecimal
- C++ Hexadecimal to Decimal
- C++ Hexadecimal to Binary
- C++ Hexadecimal to Octal
- C++ Pattern Programs
- C++ Pattern Programs
- C++ Print Diamond Pattern
- C++ Print Floyd's Triangle
- C++ Print Pascal's Triangle
- C++ Array Programs
- C++ 1D Array Program
- C++ Linear Search
- C++ Binary Search
- Find Largest Element in Array
- Find Smallest Element in Array
- Find Second Largest Element
- Find Second Smallest Element
- C++ Sum of All Elements
- C++ Multiply All Elements
- C++ Element on Even Position
- C++ Element on Odd Position
- C++ Print Even Numbers in Array
- C++ Print Odd Numbers in Array
- C++ Count Even/Odd Numbers
- C++ Sum of Even/Odd Numbers
- C++ Count Positive Negative Zero
- C++ Reverse an Array
- C++ Insert Element in Array
- C++ Delete Element from Array
- C++ Merge two Arrays
- C++ Bubble Sort
- C++ Selection Sort
- C++ Insertion Sort
- C++ Common Elements
- C++ 2D Array Programs
- C++ Add Two Matrices
- C++ Subtract Two Matrices
- C++ Transpose Matrix
- C++ Multiply Two Matrices
- C++ 3D Array Programs
- C++ String Programs
- C++ Print String
- C++ Find Length of String
- C++ Compare Two Strings
- C++ Copy String
- C++ Concatenate String
- C++ Reverse a String
- C++ Delete Vowels from String
- C++ Delete Word from String
- C++ Count Character in String
- C++ Count Word in String
- C++ Frequency of Word
- C++ Remove Spaces from String
- C++ Sort a String
- C++ Uppercase to Lowercase
- C++ Lowercase to Uppercase
- C++ Swap Two Strings
- C++ Check Anagram or Not
- C++ Capitalize All Words in String
- C++ Capitalize Specific Character
- C++ Get Numbers from String
- C++ File Programs
- C++ Read a File
- C++ Write Content to File
- C++ Append Data in File
- C++ Read & Display File
- C++ Copy a File
- C++ Merge Two Files
- Count Characters, Words in File
- C++ Capitalize All Words in File
- C++ List Files in Directory
- C++ Delete a File
- C++ Encrypt & Decrypt a File
- C++ Misc Programs
- C++ Print ASCII Value
- C++ Add Binary Numbers
- C++ Generate Random Numbers
- C++ Print Smiling Face
- C++ Days into Years, Months
- Add Two Numbers using Pointer
- C++ Print Fibonacci Series
- Generate Armstrong Numbers
- C++ Find nCr and nPr
- C++ Get IP Address
- C++ Print Date/Time
- C++ Shutdown, Restart Computer
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C++ Program to Print Prime Numbers
In this article, you will learn and get code to print prime numbers using C++ program in following ways:
- Print Prime Numbers between 1 to 100
- Print Prime Numbers in a Given Range by user at run-time
Before creating these programs on printing of prime numbers, let's first understand about it.
What is a Prime Number ?
If a number can't be divisible by any number except 1 and the number itself, then that number is called as prime number. For example, 2, 3, 5, 7, 13, 17 19 etc.
Print Prime Numbers between 1 to 100
This program prints all prime numbers between 1 to 100 using for loop. The question is, write a program in C++ to print prime numbers from 1 to 100. Here is its answer:
#include<iostream> using namespace std; int main() { int i, chk=0, j; cout<<"Prime Numbers Between 1 to 100 are:\n"; for(i=1; i<=100; i++) { for(j=2; j<i; j++) { if(i%j==0) { chk++; break; } } if(chk==0 && i!=1) cout<<i<<endl; chk = 0; } cout<<endl; return 0; }
This program was build and run under Code::Blocks IDE. Here is its sample output:
The dry run of above program goes like:
- Initial value, chk=0
- Now 1 gets initialized to i, and the condition i<=100 or 1<=100 evaluates to be true, therefore program flow goes inside the loop
- Inside the loop, there is another for loop, so 2 gets initialized to j and the condition j<i or 2<1 evaluates to be false, therefore program flow does not goes inside this loop's body
- Now the condition of if gets evaluated. There are two conditions, and between these two conditions, we've used && operator. So that, program flow only execute the statement of if's body until its both conditions evaluates to be true
- But this time, its first condition that is chk==0 or 0==0 evaluates to be true, but its second condition, that is i!=1 or 1!=1 evaluates to be false, therefore program flow does not goes inside its body
- Now 0 gets again initialized to chk and program flow goes to the update part of outer for loop and increments the value of i. So i=2
- The condition i<=100 or 2<=100 again evaluates to be true, therefore program flow again goes inside the loop
- 2 gets initialized to j and the condition j<i or 2<2 evaluates to be false
- Now the condition of if, that is, chk==0 or 0==0 evaluates to be true, and its second condition, i!=1 or 2!=1 also evaluates to be true. Since its both condition evaluates to be true, therefore program flow goes inside its body and the value of i gets printed as prime number, that is 2
- Now 0 gets initialized to ch and program flow goes to update part of for loop and increments the value of i. So i=3
- The condition i<=100 or 3<=100 again evaluates to be true, therefore program flow again goes inside the loop
- This process continues, until the condition evaluates to be false
- In this way, prime number gets printed one by one
Print Prime Numbers in a Given Range
To print all prime numbers between a particular range (entered by user) in C++ programming, do divisibility test (as done in previous program) using for loop, from 2 to one less than that number (i.e., n-1). If the number is divided to any number from 2 to one less than that number, then the number will not be prime. Otherwise, print it as a prime number as shown here in the following program.
#include<iostream> using namespace std; int main() { int st, en, i, j, chk=0; cout<<"Enter the Range\n"; cout<<"Enter the Starting Number: "; cin>>st; cout<<"Enter the Ending Number: "; cin>>en; cout<<"\nPrime Numbers between "<<st<<" and "<<en<<" are:\n"; for(i=st; i<=en; i++) { for(j=2; j<i; j++) { if(i%j==0) { chk++; break; } } if(chk==0 && i!=1) cout<<i<<endl; chk = 0; } cout<<endl; return 0; }
Here is the initial output of this program's sample run:
Now supply the two numbers as starting number and ending number say 10 and 50 to print all prime numbers between 10 and 50 as shown in the snapshot given below:
Same Program in Other Languages
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