Program to find first n prime numbers in C language

Program to find first n prime numbers in C language

In this tutorial, we will discuss the concept of an Example  Program to find first n prime numbers in C language

In this post, we are going to learn how to write a program to find the first n  prime number using for, while, and do-while loops in C programming language:

The number that can be divided by 1 and itself only. it is called the prime number

for Example 2,3,5,7,11,13….

To understand this example program, you should have previous knowledge of the following Java topics

for loop in C language

while  loop in C language

do-while  loop in C language

if statement in C language

Example program to print first n prime numbers

Print the first n prime number using the for loop

In this program, we will print the first “n” prime numbers, using for loop. first, the user is asked to enter a number randomly for n, and then the program prints the prime numbers 1 to n in C language.

Program 1

//Program to find first n prime numbers in C language
#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n,i=3,count,num;
    //declare and initialize the variable
    printf("Enter the number of prime you want\n");
    //ask input from the user and store in n
    scanf("%d",&n);

    if(n>=1){
        printf("The first %d primes numbers are: \n",n);
        //Generating prime numbers
        printf("2\n");
    }
    for(count=2; count<=n; i++){
        for(num=2; num<i; num++){
            if(i%num==0)
                break;
        }
        if(num==i){
            printf("%d \n",i);
            count++;
        }
    }
    getch();
    return 0;
}

When the above code is executed, it produces the following result

Enter the number of primes you want
The First 6 prime numbers are

2
3
5
7
11
13

Print the first n prime number using the while loop

In this program, we will print the first “n” prime numbers, using a while loop. first, the user is asked to enter a number randomly for n, and then the program prints the prime numbers 1 to n   in C language.

Program 2

//Program to find first n prime numbers in C language
#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n,i=3,count,num;
    //declare and initialize the variable
    printf("Enter the number of prime you want\n");
    //ask input from the user and store in n
    scanf("%d",&n);

    if(n>=1){
        printf("The first %d prime numbers are: \n",n);
        //Generating prime numbers
        printf("2\n");
    }
    count=2;
    while(count<=n){
            num=2;
        while(num<i){
            if(i%num==0)
                break;
     num++;
        }
        if(num==i){
            printf("%d \n",i);
            count++;
        }
        i++;
    }
    getch();
    return 0;
}

When the above code is executed, it produces the following result

Enter the number of primes you want
The first 10 prime numbers are

2
3
5
7
11
13
17
19
23
29

Print the first n prime number using the do-while loop.

In this program, we will print the first “n” prime numbers, using the do-while loop. first, the user is asked to enter a number randomly for n, and then the program prints the prime numbers 1 to n.

Program 3

//Program to find first n prime numbers in C language
#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n,i=3,count,num;
    //declare and initialize the variable
    printf("Enter the number of first n prime you want\n");
    //ask input from the user and store in n
    scanf("%d",&n);

    if(n>=1){
        printf("First %d prime numbers are: \n",n);
        //Generating prime numbers
        printf("2\n");
    }
    count=2;
   do{
            num=2;
        do{
            if(i%num==0)
                break;
     num++;
        }while(num<i);
        if(num==i){
            printf("%d \n",i);
            count++;
        }
        i++;
    } while(count<=n);
    getch();
    return 0;
}

When the above code is executed, it produces the following result

Enter the number of first n primes you want
The first 12 prime numbers are

2
3
5
7
11
13
17
19
23
29
31
37

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