Class 11: C Programming Lab Solutions (Looping Statements)

19. WAP to display n natural numbers.

#include <stdio.h>
int main() {
    int i, n;
    printf("Enter n: ");
    scanf("%d", &n);

    for(i=1;i<=n;i++)
        printf("%d ", i);

    return 0;
}

Output:

Enter n: 5
1 2 3 4 5

---

20. WAP to display first n odd numbers.

#include <stdio.h>
int main() {
    int i, n;
    printf("Enter n: ");
    scanf("%d", &n);

    for(i=1;i<=2*n;i+=2)
        printf("%d ", i);

    return 0;
}

Output:

Enter n: 5
1 3 5 7 9

---

21. WAP to display even numbers up to n.

#include <stdio.h>
int main() {
    int i, n;
    printf("Enter n: ");
    scanf("%d", &n);

    for(i=2;i<=n;i+=2)
        printf("%d ", i);

    return 0;
}

Output:

Enter n: 10
2 4 6 8 10

---

22. WAP to display sum of n numbers.

#include <stdio.h>
int main() {
    int i, n, sum=0;
    printf("Enter n: ");
    scanf("%d", &n);

    for(i=1;i<=n;i++)
        sum += i;

    printf("Sum = %d", sum);

    return 0;
}

Output:

Enter n: 5
Sum = 15

---

23. WAP to display factorial of a number provided.

#include <stdio.h>
int main() {
    int i, n, fact=1;
    printf("Enter number: ");
    scanf("%d", &n);

    for(i=1;i<=n;i++)
        fact *= i;

    printf("Factorial = %d", fact);

    return 0;
}

Output:

Enter number: 5
Factorial = 120

---

24. WAP to display product of odd numbers up to n.

#include <stdio.h>
int main() {
    int i, n, prod=1;
    printf("Enter n: ");
    scanf("%d", &n);

    for(i=1;i<=n;i+=2)
        prod *= i;

    printf("Product = %d", prod);

    return 0;
}

Output:

Enter n: 5
Product = 15

---

25. WAP to display Fibonacci series.

#include <stdio.h>
int main() {
    int n, i, a=0, b=1, c;

    printf("Enter number of terms: ");
    scanf("%d", &n);

    if(n>=1) printf("%d ", a);
    if(n>=2) printf("%d ", b);

    for(i=3;i<=n;i++){
        c=a+b;
        printf("%d ", c);
        a=b;
        b=c;
    }

    return 0;
}

Output:

Enter number of terms: 7
0 1 1 2 3 5 8

---

26. WAP to check if a number is prime or composite.

#include <stdio.h>
int main() {
    int n, i, flag=0;

    printf("Enter number: ");
    scanf("%d", &n);

    if(n<=1)
        printf("Neither Prime nor Composite");
    else{
        for(i=2;i<=n/2;i++){
            if(n%i==0){
                flag=1;
                break;
            }
        }

        if(flag==0)
            printf("Prime");
        else
            printf("Composite");
    }

    return 0;
}

Output:

Enter number: 7
Prime

---

27. WAP to display the following series and also find the sum of it.

1,2,4,7,11,16,22, ........................................................ nth term

#include <stdio.h>
int main() {
    int n, i, term=1, diff=1, sum=0;

    printf("Enter n: ");
    scanf("%d", &n);

    for(i=1;i<=n;i++){
        printf("%d ", term);
        sum += term;
        diff++;
        term += diff;
    }

    printf("\nSum = %d", sum);

    return 0;
}

Output:

Enter n: 7
1 2 4 7 11 16 22
Sum = 63

---

28. WAP to display multiplication table of any number.

#include <stdio.h>
int main() {
    int n, i;

    printf("Enter number: ");
    scanf("%d", &n);

    for(i=1;i<=10;i++)
        printf("%d x %d = %d\n", n, i, n*i);

    return 0;
}

Output:

Enter number: 5
5 x 1 = 5
5 x 2 = 10
...
5 x 10 = 50

---

29. WAP to swap two numbers.

#include <stdio.h>
int main() {
    int a, b, temp;

    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);

    temp=a;
    a=b;
    b=temp;

    printf("After swap: a=%d b=%d", a, b);

    return 0;
}

Output:

Enter two numbers: 5 10
After swap: a=10 b=5

---

30. WAP to read a number and display it in reverse order using while loop.

#include <stdio.h>

int main() {
    int n, rev = 0, rem;

    printf("Enter number: ");
    scanf("%d", &n);

    while(n != 0) {
        rem = n % 10;
        rev = rev * 10 + rem;
        n = n / 10;
    }

    printf("Reverse = %d", rev);

    return 0;
}

Output:

Enter number: 1234
Reverse = 4321

---

31. WAP to check if a number is palindrome or not.

#include <stdio.h>

int main() {
    int n, temp, rev = 0, rem;

    printf("Enter number: ");
    scanf("%d", &n);

    temp = n;

    while(n != 0) {
        rem = n % 10;
        rev = rev * 10 + rem;
        n = n / 10;
    }

    if(temp == rev)
        printf("Palindrome");
    else
        printf("Not Palindrome");

    return 0;
}

Output:

Enter number: 121
Palindrome

---

32. WAP to count number of digits in number.

#include <stdio.h>

int main() {
    int n, count = 0;

    printf("Enter number: ");
    scanf("%d", &n);

    if(n == 0) {
        count = 1;
    } else {
        while(n != 0) {
            count++;
            n = n / 10;
        }
    }

    printf("Number of digits = %d", count);

    return 0;
}

Output:

Enter number: 12345
Number of digits = 5

---

33. WAP to calculate the sum of digits in a number.

#include <stdio.h>

int main() {
    int n, sum = 0, rem;

    printf("Enter number: ");
    scanf("%d", &n);

    while(n != 0) {
        rem = n % 10;
        sum = sum + rem;
        n = n / 10;
    }

    printf("Sum of digits = %d", sum);

    return 0;
}

Output:

Enter number: 1234
Sum of digits = 10

---

34. WAP to read a number and check if is Armstrong or not.

#include <stdio.h>

int main() {
    int n, temp, rem, sum = 0;

    printf("Enter number: ");
    scanf("%d", &n);

    temp = n;

    while(n != 0) {
        rem = n % 10;
        sum = sum + rem * rem * rem;
        n = n / 10;
    }

    if(temp == sum)
        printf("Armstrong");
    else
        printf("Not Armstrong");

    return 0;
}

Output:

Enter number: 153
Armstrong

---

35. WAP to display prime numbers up to n.

#include <stdio.h>

int main() {
    int i, j, n, flag;

    printf("Enter n: ");
    scanf("%d", &n);

    for(i = 2; i <= n; i++) {
        flag = 0;

        for(j = 2; j <= i / 2; j++) {
            if(i % j == 0) {
                flag = 1;
                break;
            }
        }

        if(flag == 0)
            printf("%d ", i);
    }

    return 0;
}

Output:

Enter n: 20
2 3 5 7 11 13 17 19

---

36. WAP to display the given pattern.

1
1 2
1 2 3
1 2 3 4
1 2 3 4 5

#include <stdio.h>

int main() {
    int i, j;

    for(i = 1; i <= 5; i++) {
        for(j = 1; j <= i; j++) {
            printf("%d ", j);
        }
        printf("\n");
    }

    return 0;
}

Output:

1 
1 2 
1 2 3 
1 2 3 4 
1 2 3 4 5 

---

37. WAP to display the given pattern.

55555
4444
333
22
1

#include <stdio.h>

int main() {
    int i, j;

    for(i = 5; i >= 1; i--) {
        for(j = 1; j <= i; j++) {
            printf("%d", i);
        }
        printf("\n");
    }

    return 0;
}

Output:

55555
4444
333
22
1

---

38. WAP to display the given pattern.

*
* *
* * *
* * * *
* * * * *

#include <stdio.h>

int main() {
    int i, j;

    for(i = 1; i <= 5; i++) {
        for(j = 1; j <= i; j++) {
            printf("* ");
        }
        printf("\n");
    }

    return 0;
}

Output:

* 
* * 
* * * 
* * * * 
* * * * * 

---

39. WAP to display the given series.

1,12,123,1234, 12345,...................nth term.

#include <stdio.h>

int main() {
    int i, j, n;

    printf("Enter n: ");
    scanf("%d", &n);

    for(i = 1; i <= n; i++) {
        for(j = 1; j <= i; j++) {
            printf("%d", j);
        }
        if(i != n)
            printf(", ");
    }

    return 0;
}

Output:

Enter n: 5
1, 12, 123, 1234, 12345

---

40. WAP to find reverse of a number using do-while loop.

#include <stdio.h>

int main() {
    int n, rev = 0, rem;

    printf("Enter number: ");
    scanf("%d", &n);

    do {
        rem = n % 10;
        rev = rev * 10 + rem;
        n = n / 10;
    } while(n != 0);

    printf("Reverse = %d", rev);

    return 0;
}

Output:

Enter number: 5678
Reverse = 8765

---

41. WAP to check Armstrong number using do-while loop.

#include <stdio.h>

int main() {
    int n, temp, rem, sum = 0;

    printf("Enter number: ");
    scanf("%d", &n);

    temp = n;

    do {
        rem = n % 10;
        sum = sum + rem * rem * rem;
        n = n / 10;
    } while(n != 0);

    if(temp == sum)
        printf("Armstrong");
    else
        printf("Not Armstrong");

    return 0;
}

Output:

Enter number: 153
Armstrong