Loop Exercise 2

On this page, you will get some loop exercise and their solution. Try it by yourself first then if you can not do then see the solution.

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Exercise 11:

Write a program (WAP) that will calculate the result for the first Nth terms of the following series. [In that series sum, dot sign (.) means multiplication]
1².2 + 2².3 + 3².4 + 4².5 + …….

Solution:

  #include<stdio.h>
  int main() {
    int n;
    int sum = 0;
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        int term = (i * i);
        sum += (i+1) * term;
    }
    printf("Result: %d\n", sum);
    return 0;
  }

Output:

  7
  Result: 924

Exercise 12:

Write a program (WAP) that will print print Fibonacci series upto N^th terms.
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89,……N.

Solution:

  #include<stdio.h>
  int main() {
    int n, i;
    int first = 1, second = 1, next;
    scanf("%d", &n);
    if(n==1){
      printf("1");
    }else{
      printf("%d, %d", first, second);
      for (i = 3; i <= n; i++) {
        next = first + second;
        printf(", %d", next);
        first = second;
        second = next;
      }
    }
  return 0;
  }

Output:

    7
    1, 1, 2, 3, 5, 8, 13

Exercise 13:

Write a program (WAP) that will print the factorial (N!) of a given number N. Please see the sample input output.

Solution:

  #include<stdio.h>
  int main() {
    int n, i;
    unsigned long long fact = 1;
    scanf("%d", &n);
    if (n < 0){
      printf("Error!"); 
    }
    else {
        for (i = 1; i <= n; ++i) {
          fact *= i;
        }
        printf("%d! = %d ", n,n);
        for (i = n-1; i >= 0; i--) {
          if(i==0){
            break;
          }
          printf("x %d ", i);
        }
      printf("= %d",fact);
    }
    return 0;
  }

Output:

    4
    4! = 4 X 3 X 2 X 1 = 24

Exercise 14:

Write a program (WAP) that will find ⁿC_r where n >= r; n and r are integers.

Solution:

  #include<stdio.h>
  int fact(int z){
    int f = 1, i;
    if (z == 0){
        return(f);
    }
    else{
        for (i = 1; i <= z; i++){
            f = f * i;
        }
    }
    return(f);
  }
  int main(){
    int n, r, result;
    scanf("%d%d", &n, &r);
    result = fact(n) / (fact(r) * fact(n - r));
    printf("%d", result);
  }

Output:

  7 7
  1 

Exercise 15:

Write a program (WAP) that will find x^y (x to the power y) where x, y are positive integers.

Solution:

  #include<stdio.h>
  int main() {
    int x, y;
    long long result = 1;
    scanf("%d%d", &x, &y);
    for(int i = 0; i < y; i++) {
      result *= x;
    }
    printf("%lld\n", result);
    return 0;
  }

Output:

    5 2
    25    

Exercise 16:

WAP that will find the GCD (greatest common divisor) and LCM (least common multiple) of two positive integers.

Solution:

  #include<stdio.h>
  int gcd(int a, int b) {
    while (b != 0) {
      int temp = b;
      b = a % b;
      a = temp;
    }
    return a;
  }
  
  int main() {
    int x, y;
    int gcd_val, lcm_val;
    scanf("%d %d", &x, &y);
    gcd_val = gcd(x, y);
    lcm_val = (x * y) / gcd_val;
    printf("GCD: %d\n", gcd_val);
    printf("LCM: %d\n", lcm_val);
    return 0;
  }

Output:

  5 7
  GCD: 1
  LCM: 35

Exercise 17:

WAP that will determine whether a number is prime or not.

Solution:

  #include<stdio.h>
  int main() {
    int n, i, flag = 0;
    scanf("%d", &n);
    for (i = 2; i <= n/2; ++i) {
      if (n % i == 0) {
        flag = 1;
        break;
      }
    }

    if (n == 1) {
      printf("Not prime");
    }
    else {
      if (flag == 0){
        printf("Prime\n");
      }      
      else{
        printf("Not prime\n");
      }        
    }
    return 0;
  }

Output:

  2
  Prime

Exercise 18:

WAP that will determine whether an integer is palindrome number or not.

Solution:

  #include<stdio.h>
  int main() {
    int n, reversed = 0, remainder, original;
    scanf("%d", &n);
    original = n;
    while (n != 0) {
        remainder = n % 10;
        reversed = reversed * 10 + remainder;
        n /= 10;
    }
    if(original == reversed){
      printf("Yes\n"); 
    }
    else{
      printf("No\n");
    }
    return 0;
  } 

Output:

 222
 Yes

Exercise 19:

WAP that will calculate following mathematical function for the input of x. Use only the series to solve the problem.
Sinx = x- (x³)/3! + (x⁵)/5! - (x⁷)/7! + ......- ∞.

Solution:

  #include<stdio.h>
  #include<math.h>
  int main() {
    double x, term, sum = 0;
    int sign = 1, fact = 1;
    scanf("%lf", &x);
    for (int i = 1; i <= 15; i += 2) {
      term = sign * pow(x, i) / fact;
      sum += term;
      sign *= -1;
      fact *= (i+1) * (i+2);
    }
    printf("%.3lf\n", sum);
    return 0;
  }

Output:

  1
  0.841

Exercise 20:

Write a program that takes an integer number n as input and find out the sum of the following series up to n terms.
1 + 12 + 123 + 1234 + …….

Solution:

  #include<stdio.h>
  int main() {
    int n;
    scanf("%d", &n);
    int sum = 0, term = 0;
    for (int i = 1; i <= n; i++) {
        term = term * 10 + i;
        sum += term;
    }
    printf("%d",sum);
    return 0;
  }

Output:

  3
  136