In this article, you’ll learn how to print all prime number between two given number in C++ language without giving input from the keyboard or giving input from the keyboard.
Q: what is the prime number
Ans: A natural number which only divided by itself and 1 is called a prime number and you also say that a prime number is a natural number which is greater than 1 and cannot be formed by multiplying two natural number.
- 1 is not a prime number.
- 2 is the smallest prime number and only even prime number.
- Example of prime number 2,3,5,7,11,13 etc.
To print all prime number between two given number we generally use the following steps:
- First, we take two number then add 1 in the first number and subtract 1 in the second number to check prime number between two intervals number.
- We use two for loop first, for loop for checking all number between the intervals and second for loop to check prime number.
- If second for loop is true, then it means the number is not a prime number and increments the number check again
- If second for loop is false, then it checks again
- if(i==x) then it a prime number and check again for the first for loop.
Example 1: write a program in C++ language to print all prime number between two given number, without input from keyboard
#include<iostream>
using namespace std; int main() { int f1=3,f2=60,x,i; for(x=f1+1;x<=f2-1;x++){ for(i=2;i<x;i++) if(x%i==0) break; if(i==x) cout<<“\n”<< x; } return 0; } |
The Output of this program:
5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 |
Example 2: write a program in C++ language to print all prime number between two given number, with input from the keyboard
Solution:
#include<iostream>
using namespace std; int main() { int f1,f2,x,i; cout<<“Enter first number: “; cin>>f1; cout<<“Enter second number: “; cin>>f2; for(x=f1+1;x<=f2-1;x++){ for(i=2;i<x;i++) if(x%i==0) break; if(i==x) cout<<“\n”<< x; } return 0; } |
The Output of this program:
Enter first number: 1 Enter second number: 100
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 |
Example 3: write a program in C++ language to print all prime number including two given number, with input from keyboard Solution:
#include <stdio.h>
#include <conio.h> int main() { int f1,f2,x,i; printf(“Enter first number: “); scanf(“%d”,&f1); printf(“Enter second number: ” ); scanf(“%d”,&f2); for(x=f1;x<=f2;x++){ for(i=2;i<x;i++) if(x%i==0) break; if(i==x) printf(“%d “,x); } return 0; } |
The output of this program:
Enter first number: 2 Enter second number: 23
2 3 5 7 11 13 17 19 23 |