1.
using while ,do while and for loops :
**
***
****
*****
for loop :
#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;
while loop:
#include <stdio.h>
int main() {
int i = 1, j;
while (i <= 5) {
j = 1;
while (j <= i) {
printf("* ");
j++;
printf("\n");
i++;
return 0;
do-while loop:
#include <stdio.h>
int main() {
int i = 1, j;
do {
j = 1;
do {
printf("* ");
j++;
} while (j <= i);
printf("\n");
i++;
} while (i <= 5);
return 0;
2. using while ,do while and for loops :
*****
****
***
**
for loop:
#include <stdio.h>
int main() {
for (int i = 5; i > 0; i--) {
for (int j = 0; j < i; j++) {
printf("* ");
printf("\n");
return 0;
while loop:
#include <stdio.h>
int main() {
int i = 5;
while (i > 0) {
int j = 0;
while (j < i) {
printf("* ");
j++;
printf("\n");
i--;
return 0;
do-while loop:
#include <stdio.h>
int main() {
int i = 5;
do {
int j = 0;
do {
printf("* ");
j++;
} while (j < i);
printf("\n");
i--;
} while (i > 0);
return 0;
3. using while ,do while and for loops :
*****
****
***
**
for loop:
#include <stdio.h>
void main() {
for (int i = 0; i < 2; i++) {
for (int s = 0; s < i * 2; s++) printf(" "); // Modify this for left alignment
for (int j = 5 - i; j > 0; j--) printf("* ");
printf("\n");
for (int i = 3; i > 0; i--) {
for (int s = 0; s < (5 - i) * 2 + 4; s++) printf(" "); // Adjusted spaces for continuous alignment
for (int j = 0; j < i; j++) printf("* "); // Stars
printf("\n");
while loop:
#include <stdio.h>
void main() {
int i = 0;
while (i < 2) {
int s = 0;
while (s < i * 2) {
printf(" "); // Modify this for left alignment
s++;
int j = 5 - i;
while (j > 0) {
printf("* ");
j--;
printf("\n");
i++;
i = 3;
while (i > 0) {
int s = 0;
while (s < (5 - i) * 2 + 4) {
printf(" "); // Adjusted spaces for continuous alignment
s++;
}
int j = 0;
while (j < i) {
printf("* "); // Stars
j++;
printf("\n");
i--;
do-while loop:
#include <stdio.h>
int main() {
int i = 0, j, s;
do {
s = 0;
do {
printf(" ");
s++;
} while (s < i * 2);
j = 5 - i;
do {
printf("* ");
j--;
} while (j > 0);
printf("\n");
i++;
} while (i < 2);
i = 3;
do {
s = 0;
do {
printf(" ");
s++;
} while (s < (5 - i) * 2 +4);
j = 0;
do {
printf("* ");
j++;
} while (j < i);
printf("\n");
i--;
} while (i > 0);
return 0;
6. 1
22
333
4444
55555
for loop:
#include <stdio.h>
int main() {
int i, j;
for (i = 1; i <= 5; i++) {
for (j = 1; j <= i; j++) {
printf("%d",i);
printf("\n");
return 0;
7. 1
12
123
1234
12345
#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;
8. 1
01
101
0101
10101
#include <stdio.h>
int main() {
int i, j;
for (i = 1; i <= 5; i++) {
for (j = 1; j<=i; j++) {
printf("%d",(i+j)%2);
printf("\n");
return 0;
9. 5
44
333
2222
11111
#include <stdio.h>
int main() {
int i, j;
for (i = 5; i >= 1; i--) {
for (j = 1; j <= (6 - i); j++) {
printf("%d ", i);
printf("\n");
return 0;
10. 5
54
543
5432
54321
include <stdio.h>
int main() {
int i, j;
for (i = 1; i <= 5; i++) {
for (j = 5; j >= (6 - i); j--) {
printf("%d ", j);
printf("\n");
return 0;
11. 1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
#include <stdio.h>
int main() {
int num = 1;
for (int i = 1; i <= 5; i++) {
for (int j = 1; j <= i; j++) {
printf("%d ", num++);
printf("\n");
return 0;
12.without using nested loops :
**
***
****
*****
#include <stdio.h>
int main() {
int i = 1;
char str[] = "";
while (i <= 5) {
printf("%.*s*\n", i * 2 - 1, "**********");
i++;
return 0;
14. Write a program to print all prime numbers between 2 given integers.
#include <stdio.h>
int main() {
int start, end, i, j, isPrime;
printf("Enter two numbers: ");
scanf("%d %d", &start, &end);
printf("Prime numbers between %d and %d are:\n", start, end);
for (i = start; i <= end; i++) {
if (i < 2)
continue;
isPrime = 1;
for (j = 2; j < i; j++) {
if (i % j == 0) {
isPrime = 0;
break;
if (isPrime) printf("%d ", i);
return 0;
