# Array Exercise 1

## Exercise 1:

Write a program (WAP) that will take n integer numbers into an array, and then print all the integers into reverse order (from the last valid index to index 0).

Sample Input Sample Output
5
1 2 3 4 5
5 4 3 2 1
6
2 8 3 9 0 1
1 0 9 3 8 2

### Solution:

``````
#include<stdio.h>
int main(){
int n, i;
scanf("%d", &n);
int arr[n];
for(i=0; i<n; i++) {
scanf("%d", &arr[i]);
}

printf("Reversed array: ");
for(i=n-1; i>=0; i--) {
printf("%d ", arr[i]);
}
return 0;
}
```
```

#### Output:

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

## Exercise 2:

Write a program (WAP) that WAP that will take n integer numbers into an array, and then sum up all the integers in that array.

Sample Input Sample Output
5
1 2 3 4 5
15
6
2 8 3 9 0 1
23

### Solution:

``````
#include<stdio.h>
int main(){
int n, i, sum=0;
scanf("%d", &n);
int arr[n];
for(i=0; i<n; i++) {
scanf("%d", &arr[i]);
sum += arr[i];
}

printf("%d\n", sum);
return 0;
}
```
```

#### Output:

``````
5
1 2 3 4 5
15
```
```

## Exercise 3:

Write a program (WAP) that will take n integer numbers into an array, and then sum up all the even integers in that array.

Sample Input Sample Output
5
1 2 3 4 5
15
6
2 8 3 9 0 1
23

### Solution:

``````
#include<stdio.h>
int main(){
int n, i, sum_even=0;
scanf("%d", &n);
int arr[n];
for(i=0; i<n; i++) {
scanf("%d", &arr[i]);
if(arr[i] % 2 == 0) {
sum_even += arr[i];
}
}

printf("%d\n", sum_even);
return 0;
}
```
```

#### Output:

``````
5
1 2 3 4 5
6
```
```

## Exercise 4:

Write a program (WAP) that will take n integer numbers into an array, and then sum up all the even indexed integers in that array.

Sample Input Sample Output
5
1 2 3 4 5
9
6
2 8 3 9 0 1 5
5

### Solution:

``````
int main() {
int n, i, sum = 0;
scanf("%d", &n);
int arr[n];
for (i = 0; i < n; i++) {
scanf("%d", &arr[i]);
if (i % 2 == 0) { // check if index is even
sum += arr[i];
}
}
printf("%d\n", sum);
return 0;
}
```
```

#### Output:

``````
5
1 2 3 4 5
9
```
```

## Exercise 5:

Write a program (WAP) that will take n integer numbers into an array, and then reverse all the integers within that array. Finally print them all from 0 index to last valid index.

Sample Input Sample Output
5
1 2 3 4 5
5 4 3 2 1
6
2 8 3 9 0 1
1 0 9 3 8 2

### Solution:

``````
#include<stdio.h>
int main(){
int n;
scanf("%d", &n);
int arr[n];
for(int i=0; i<n; i++) {
scanf("%d", &arr[i]);
}

for(int i=n-1; i>=0; i--) {
printf("%d ", arr[i]);
}
return 0;
}
```
```

#### Output:

``````
5
1 2 3 42 2
2 42 3 2 1
```
```

## Exercise 6:

Write a program (WAP) that will take n integer numbers into an array, and then find the maximum -minimum among them with its index position.

Sample Input Sample Output
5
1 2 3 4 5
Max: 5, Index: 4
Min: 1, Index: 0
6
2 8 3 9 0 1
Max: 9, Index: 3
Min: 0, Index: 4

### Solution:

``````
#include<stdio.h>
int main(){
int n, arr[100], max, min, max_index, min_index, i;
scanf("%d", &n);
for (i = 0; i < n; i++) {
scanf("%d", &arr[i]);
}
max = arr[0];
min = arr[0];
max_index = 0;
min_index = 0;
for (i = 1; i < n; i++) {
if (arr[i] > max) {
max = arr[i];
max_index = i;
}
if (arr[i] < min) {
min = arr[i];
min_index = i;
}
}
printf("Max: %d, Index: %d\n", max, max_index);
printf("Min: %d, Index: %d\n", min, min_index);
return 0;
}
```
```

#### Output:

``````
5
1 2 3 4 5
Max: 5, Index: 4
Min: 1, Index: 0
```
```

## Exercise 7:

Write a program (WAP) that will take n alphabets into an array, and then count number of vowels in that array.

Sample Input Sample Output
7
AKIOUEH
Count: 5
29
UNITEDINTERNATIONALUNIVERSITY
Count: 13

### Solution:

``````
#include<stdio.h>
int main(){
int n, i, count = 0;
scanf("%d", &n);
char arr[100];
for(i = 0; i < n; i++) {
scanf(" %c", &arr[i]);// space is for separate the each char
}

for(i = 0; i < n; i++) {
if(arr[i] == 'a' || arr[i] == 'e' || arr[i] == 'i' || arr[i] == 'o' || arr[i] == 'u' ||
arr[i] == 'A' || arr[i] == 'E' || arr[i] == 'I' || arr[i] == 'O' || arr[i] == 'U') {
count++;
}
}

printf("Count: %d", count);

return 0;
}
```
```

#### Output:

``````
29
UNITEDINTERNATIONALUNIVERSITY
Count: 13
```
```

## Exercise 8:

Write a program (WAP) that will take n integers into an array, and then search a number into that array. If found then print its index. If not found then print “NOT FOUND”.

Sample Input Sample Output
8
7 8 1 3 2 6 4 3
3
FOUND at index position: 3, 7
8
7 8 1 3 2 6 4 3
5

### Solution:

``````
#include<stdio.h>
int main(){
int n, i, num, found = 0,k=0;
scanf("%d", &n);
int arr[n],result[n];
for (i = 0; i < n; i++) {
scanf("%d", &arr[i]);
}
scanf("%d", &num);
for (i = 0; i < n; i++) {
if (arr[i] == num) {
result[k++]= i;
found = 1;
}
}

if (found == 0) {
}
else{
printf("FOUND at index position: ");
for(int i = 0; i < k; i++ ){
if(i==k-1){ //for printing commas
printf("%d",result[i]);
}
else{
printf("%d, ",result[i]);
}
}
}

return 0;
}
```
```

#### Output:

``````
8
7 8 1 3 2 6 4 3
3
FOUND at index position: 3, 7
```
```

## Exercise 9:

Write a program (WAP) that will take n integers into an array A, and then copy all numbers in reverse order from array A to another array B. Finally show all elements of both array A and B.

Sample Input Sample Output
8
7 8 1 3 2 6 4 3
3
Array A : 7 8 1 3 2 6 4 3
Array B : 3 4 6 2 3 1 8 7
3
3 2 1
Array A : 3 2 1
Array B : 1 2 3

### Solution:

``````
#include<stdio.h>
int main() {
int n, i;
scanf("%d", &n);
int A[n], B[n];
for (i = 0; i < n; i++) {
scanf("%d", &A[i]);
}

for (i = 0; i < n; i++) {
B[n - i - 1] = A[i];
}

printf("\nArray A: ");
for (i = 0; i < n; i++) {
printf("%d ", A[i]);
}
printf("\nArray B: ");
for (i = 0; i < n; i++) {
printf("%d ", B[i]);
}

return 0;
}
```
```

#### Output:

``````
3
3 2 1
Array A: 3 2 1
Array B: 1 2 3
```
```

## Exercise 10:

Write a program (WAP) that will first take n integers into an array A and then m integers into array B. Now swap all elements between array A and B. Finally show all elements of both array A and B.

Sample Input Sample Output
8
7 8 1 3 2 6 4 3
3
3 2 1
Array A : 3 2 1
Array B : 7 8 1 3 2 6 4 3

### Solution:

``````
#include<stdio.h>
int main() {
int n, m, i, temp;
// take input for array A
scanf("%d", &n);
int A[n];
for(i=0; i<n; i++) {
scanf("%d", &A[i]);
}
// take input for array B
scanf("%d", &m);
int B[m];
for(i=0; i<m; i++) {
scanf("%d", &B[i]);
}

// swap elements between array A and B
for(i=0; i<n && i<m; i++) {
temp = A[i];
A[i] = B[i];
B[i] = temp;
}

// display elements of array A and B
printf("Array A: ");
for(i=0; i<n; i++) {
printf("%d ", A[i]);
}
printf("\n");

printf("Array B: ");
for(i=0; i<m; i++) {
printf("%d ", B[i]);
}
return 0;
}
```
```

#### Output:

``````
8
7 8 1 3 2 6 4 3
3
3 2 1
8
Array A: 3 2 1 3 2 6 4 3
Array B: 7 8 1
```
```

## Exercise 11:

Write a program (WAP) WAP that will take n positive integers into an array A. Now find all the integers that are divisible by 3 and replace them by -1 in array A. Finally show all elements of array A.

Sample Input Sample Output
8
7 8 1 3 2 6 4 3
7 8 1 -1 2 -1 4 -1
3
3 2 1
-1 2 1

### Solution:

``````
#include<stdio.h>
int main() {
int n, i;
scanf("%d", &n);
int a[n];
for(i=0; i<n; i++) {
scanf("%d", &a[i]);
}
// Replacing elements divisible by 3 with -1
for(i=0; i<n; i++) {
if(a[i]%3 == 0) {
a[i] = -1;
}
}
// Printing array elements
for(i=0; i<n; i++) {
printf("%d ", a[i]);
}
return 0;
}
```
```

#### Output:

``````
8
7 8 1 3 2 6 4 3
7 8 1 -1 2 -1 4 -1
```
```