Question 1

What are the three types of loops in C?

Accepted Answer

For, While, Do/While

Question 2

What is a pre-test loop? Give an example.

Accepted Answer

A loop where the condition is tested before executing the body (e.g. while, for )

Question 3

What is a post-test loop? Give an example.

Accepted Answer

A loop where the condition is tested after executing the body (e.g do/while)

Question 4

How do you create an infinite loop?

Accepted Answer

Using a loop with a condition that is always true e.g while(1) or for(;;)

Question 5

what does break do inside a loop?

Accepted Answer

Exits loop immediately

Question 6

what does continue do inside a loop?

Accepted Answer

skips the rest of the current iteration and continues to the next iteration

Question 7

what does return do inside a function?

Accepted Answer

exits the function immediately and optionally returns a value.

Question 8

Which libraries are needed to generate random numbers in C?

Accepted Answer

stlib.h and time.h

Question 9

How do you seed the random number generator?

Accepted Answer

using srand(time(NULL));

Question 10

How do you generate a random integer in a range [min, max]?

Accepted Answer

rand() % (max - min +1) +min

Question 11

What is the purpose of srand()?

Accepted Answer

To initialize the random number generator to produce different sequences each run

Question 12

How do you declare a 1D array of 5 integers?

Accepted Answer

int arr[5];

Question 13

How do you declare a 2D array of 3x4 integers?

Accepted Answer

int arr[3][4];

Question 14

How can you initialize an array when declaring it?

Accepted Answer

int arr[5] = {1, 2, 3, 4, 5,};

Question 15

what happens if you exceed an arrays size?

Accepted Answer

accessing an out of bounds index causes undefined behavior

Question 16

What is the difference between an element position and an element index?

Accepted Answer

Index: actual number used in code to access an element 
element position: logical placement in the array ( 1st , 2nd..)

Question 17

How do you copy elements from one array to another?

Accepted Answer

Using a loop: for(int i=0; i <n; ++i) { arr2[i]=arr1[i];}

Question 18

How do you fill a 2D array with random numbers?

Accepted Answer

Using a nested loop: 
for(int i=0; i < rows; i++) {
for (int j=0; j < cols; j++) {
arr[i][j] = rand() % range + offset;
}
}

Question 19

Predict the output:

for(int i=0;i<5;i++){
    if(i==2) break;
    printf("%d ", i);
}

Accepted Answer

01

Question 20

Predict the output if break is replaced with continue in the previous example.

Accepted Answer

0134

Question 21

Write a for loop to print numbers 1–10.

Accepted Answer

for( int i=1; i<=10; i++) { printf("%d ", i);}

Question 22

write a while loop to sum numbers 1-5

Accepted Answer

int sum= 0, i=1;
while(i<=5) { sum +=i; i++}

Question 23

write a do while loop that prints hello 3 times

Accepted Answer

int i=0;
do{ 
printf("hello
"); i++
} while(i<3);

Question 24

Write code to generate a random number between 0–99.

Accepted Answer

rand() % 100;

Question 25

Write code to generate a random number between 50–100.

Accepted Answer

rand() % 51 +50

Question 26

what is the purpose of srand()?

Accepted Answer

to initialize the random number generator so sequences differ each run

Question 27

why is time(NULL) used with srand()

Accepted Answer

it provides a changing seed based on the current time

Question 28

write a loop to print 5 random numbers 1-10

Accepted Answer

for (int i=0; i <5; ++i) printf("%d", rand()%10 +1;

Question 29

Fill a 1D array with random numbers 1–20.

Accepted Answer

for(int i=0;i<5;i++) arr[i]=rand()%20 + 1;

Question 30

Calculate the sum of a 1D array using a loop.

Accepted Answer

int sum=0;
for(int i=0;i<5;i++) sum+=arr[i];

Question 31

How do you initialize a 2D array at declaration?

Accepted Answer

int arr[2][3]={{1,2,3},{4,5,6}};

Question 32

Write nested loops to fill a 3x3 array with numbers 1–9.

Accepted Answer

int val=1;
for(int i=0;i<3;i++){
    for(int j=0;j<3;j++){
        arr[i][j]=val++;
    }
}

Question 33

Write nested loops to print a 3x3 array in grid form

Accepted Answer

for(int i=0;i<3;i++){
    for(int j=0;j<3;j++){
        printf("%d ", arr[i][j]);
    }
    printf("
");
}

Question 34

How do you fill a 2D array with random numbers 0–9?

Accepted Answer

for(int i=0;i<rows;i++){
    for(int j=0;j<cols;j++){
        arr[i][j]=rand()%10;
    }
}

Question 35

How do you traverse a 2D array backward?

Accepted Answer

for(int i=rows-1;i>=0;i--){
    for(int j=cols-1;j>=0;j--) printf("%d ",arr[i][j]);
}

Question 36

Fill a 1D array with random numbers 1–50, then print even numbers only.

Accepted Answer

for(int i=0;i<5;i++){
    arr[i]=rand()%50 + 1;
    if(arr[i]%2==0) printf("%d ", arr[i]);
}

Question 37

Fill a 2D array with random numbers, then find the largest element.

Accepted Answer

int max=arr[0][0];
for(int i=0;i<rows;i++){
    for(int j=0;j<cols;j++){
        if(arr[i][j]>max) max=arr[i][j];
    }
}

Question 38

Use a loop to sum all elements in a 2D array.

Accepted Answer

int sum=0;
for(int i=0;i<rows;i++){
    for(int j=0;j<cols;j++){
        sum+=arr[i][j];
    }
}

Question 39

hat limitation does a C array have?

Accepted Answer

Fixed size; cannot resize once declared.

Question 40

What is the difference between int arr[5] and int *arr?

Accepted Answer

arr[5] is a fixed-size array; int *arr is a pointer, can point to dynamic memory.

Question 41

Fill an array with random numbers in range [10,30].

Accepted Answer

arr[i] = rand() % 21 + 10;

Question 42

Declare, initialize, and print a 2x2 array without loops.

Accepted Answer

int arr[2][2]={{1,2},{3,4}};
printf("%d %d
%d %d", arr[0][0], arr[0][1], arr[1][0], arr[1][1]);

Question 43

Use a loop to fill a 1D array with values equal to their index squared.

Accepted Answer

for(int i=0;i<5;i++) arr[i]=i*i;

Question 44

difference between break and return

Accepted Answer

return exits the entire function, break exits only the current loop or switch and continues to next block of code

Question 45

pre increment

Accepted Answer

++i meaning increment first then use the value  the variable is increased before its used in an expression

Question 46

post increment

Accepted Answer

i++ meaning use the current value first then increment

Question 47

we can store multiple types in an array and preserve data

Accepted Answer

false, only one data at a time

Question 48

the index of an array can be any integral type

Accepted Answer

true

Question 49

given an array of n values the last item is indexed n-1

Accepted Answer

true

Question 50

arrays cannot be resized after they are declared

Accepted Answer

false, dynamic arrays can using memory functions

Question 51

any loop requires three items

Accepted Answer

initialization i=0;, update i++, conditioni<10

Question 52

if any of the 3 required items are missing a loop may easily become

Accepted Answer

infinite

Question 53

declare a 4 x 4 2 dimensional array and use looping to fill it with characters as shown here without using scanf()

Accepted Answer

#include <stdio.h>

int main(void) {
    char letters[4][4];
    char ch = 'A'; // starting character

    for (int row = 0; row < 4; row++) {
        for (int col = 0; col < 4; col++) {
            letters[row][col] = ch;
            ch++; // mo

Exam II

Programming I

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