
1.Find out the perfect number using C program
C program to check perfect number:
Program: #include int main(){ int n,i=1,sum=0; printf("Enter a number: "); scanf("%d",&n); while(i if(n%i==0) sum=sum+i; i++; } if(sum==n) printf("%d is a perfect number",i); else printf("%d is not a perfect number",i); return 0; }
Output: Enter a number: 6 6 is a perfect number
2.C program to print perfect numbers from 1 to 100
C program to print perfect numbers from 1 to 100:
Program: #include int main(){ int n,i,sum; printf("Perfect numbers are: "); for(n=1;n<=100;n++){ i=1; sum = 0; while(i if(n%i==0) sum=sum+i; i++; } if(sum==n) printf("%d ",n); } return 0; }
Output: Perfect numbers are: 6 28
3.C program to check whether a number is Armstrong or not
C program to check whether a number is Armstrong or not:
Program: #include int main(){ int num,r,sum=0,temp; printf("Enter a number: "); scanf("%d",&num); temp=num; while(num!=0){ r=num%10; num=num/10; sum=sum+(r*r*r); } if(sum==temp) printf("%d is an Armstrong number",temp); else printf("%d is not an Armstrong number",temp); return 0; }
Output: Enter a number: 153 153 is an Armstrong number
4.C program to find given number is prime or not
C program to find given number is prime or not:
Program: #include int main(){ int num,i,count=0; printf("Enter a number: "); scanf("%d",&num); for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) printf("%d is a prime number",num); else printf("%d is not a prime number",num); return 0; }
Output: Enter a number: 5 5 is a prime number
5.C program to find sum of prime numbers
C program to find sum of prime numbers:
Program: #include int main(){ int num,i,count,min,max,sum=0; printf("Enter min range: "); scanf("%d",&min); printf("Enter max range: "); scanf("%d",&max); for(num = min;num<=max;num++){ count = 0; for(i=2;i<=num/2;i++){ if(num%i==0){ count++; break; } } if(count==0 && num!= 1) sum = sum + num; } printf("Sum of prime numbers is: %d ",sum); return 0; }
Output: Enter min range: 50 Enter max range: 100

