C Programming

Problem 1 swapping two number without function

#include<stdio.h>

int main()

{

int x,y,z;

scanf("%d%d",&x,&y);//x=2,y=5

x=x+y;//7

y=x-y;//7-5=2

x=x-y;//7-2=5

printf("%d %d",x,y);

return 0;

}

Problem 2 : Average of three number without function

#include<stdio.h>

int main()

{

int a,b,c;

float d;

scanf("%d%d%d",&a,&b,&c);

printf("%d %d %d ", a,b,c);

d=(a+b+c)/3.00;// explicit type casting

printf("%.2f", d);

return 0;

}

 Problem 3 : Armstrong number 

//1^3+5^3+3^3=153

#include<stdio.h>

#include<math.h>

int main()

{

int n, rem, sum=0, b;

scanf("%d",&n);

b=n;

while(n>0)

{

rem=n%10;

n=n/10;

sum=sum+pow(rem,3);

}

if(sum==b)

{

printf("Armstrong number");

}

else

{

printf("Not Armstrong Number");

}

return 0;

}

Problem 4 : Basic four mathematical operation with the help of switch case

#include<stdio.h>

int main()

{

float a,b,c;

char ch;

printf("enter the 1st no :");

scanf("%f", &a);

fflush(stdin);//clear the input buffer

printf("enter user device to perform the operation: ");

scanf("%c",&ch);

printf("enter the 2nd no :");

scanf("%f",&b);

switch(ch)

{

case'+': c=a+b;

printf("output=%f",c);

break;

case '-':c=a-b;

printf("output=%f",c);

break;

case '*':c=a*b;

printf("output=%f",c);

break;

case '/':c=a/b;

printf("output=%f",c);

break;

}

return 0;

}

Problem 5 : Check a number is prime number or not 

#include<stdio.h>

void prime(int);

int main()

{

int x;

scanf("%d",&x);

prime(x);

return 0;

}

void prime(int a)

{

int i, c=0;

for(i=1;i<=a/2;i++)

{

if(a%i==0)

{

c++;

}

}

if(c==1)

   printf("Prime");

else

printf("Not prime");

}

Problem 6 : Find Factorial of a number 

#include<stdio.h>

void fact(int);

int main()

{

int x;

scanf("%d",&x);

if(x>0)

{

fact(x);

}

else

{

printf("Enter postive number");

}

return 0;

}

void fact (int a)

{

int f=1, i;

for(i=1;i<=a;i++)

{

f=f*i;

}

printf("The factorial of %d is %d ", a,f);

}