#include<stdio.h>
#include<conio.h>
#include<math.h>
int main()
{
//price 12.00
//tip 20
//tax8
//Your Output 15
//round function in math.h headerfile
	double price;
	float tip,tax;
	scanf("%lf%f%f",&price,&tip,&tax);
	tip=(price/100)*tip;
	tax=(price/100)*tax;
	int total = (int)round(price+tip+tax);
	printf("%d",total);
	return 0;
}

OUTPUT

12.00  //price
20      //tip
8      //tax
15     total cost round figure.

#include<stdio.h>
#include<conio.h>
int main()
{
	int i,num,sum=0,hmarks;
	int arr[20];
	float avg;
	printf("\nenter the number of students :");
	scanf("%d",&num);
	printf("\nenter the marks of the students\n");
	for(i=0;i<num;i++)
	{
		scanf("\n%d",&arr[i]);
		sum=sum+arr[i];
	}
	printf("\ntotal marks of students :%d",sum);
	avg=sum/num;
	printf("\naverage marks of the students :%f",avg);
	for(i=0;i<num;i++)
	{
		
	}
	return 0;
}

#include<stdio.h>
#include<conio.h>
int main()
{
	int a,b;
	printf("\nenter the value of a = ");
	scanf("%d",&a);
	printf("\nenter the value of b = ");
	scanf("%d",&b);
	a=a+b;
	b=a-b;
	a=a-b;
	printf("\nafter swaping the values");
	printf("\nvalue of a = %d",a);
	printf("\nvlaue of b = %d",b);
	return 0;
}

#include<stdio.h>
#include<conio.h>
int main()
{
	int a,b,c,d,sum;
	scanf("%d%d%d%d",&a,&b,&c,&d);
	if((a>b)&&(a>c)&&(a>d))
	{
		printf("%d",a);
	}
	else
	{
		if((b>c)&&(b>d))
		{
			printf("%d",b);
		}
		else
		{
			if((c>d))
			{
				printf("%d",c);
			}
			else
			{
				printf("%d",d);
			}
		}
	}
	return 0;
}

#include<stdio.h>
#include<conio.h>
int main()
{
	int a,b,isum,isub;
	float x,y,sum,sub;
	scanf("%d%d",&a,&b);
	scanf("%f%f",&x,&y);
	isum=a+b;
	printf("%d",isum);
	isub=a-b;
	printf(" %d",isub);
	sum=x+y;
// float=25.00000 but when you use 1.1 ( float=25.0) 
	printf("\n%1.1f",sum);
	sub=x-y;
	printf(" %1.1f",sub);
	return 0;
}

#include<stdio.h>
#include<conio.h>
int main()
{
	//C  Language   Welcome To C!!
	char ch;
	scanf("%c",&ch);
	printf("%c\n",ch);
	char strn[50],sent[100];
	scanf("%s",&strn);
	printf("%s\n",strn);
//	char sent[100];
	scanf("\n");
	gets(sent);
	printf("%s",sent);
}

#include<stdio.h>
#include<conio.h>
int main()
{
	char str[100];
	gets(str);
	printf("Hello, Word.\n%s",str);
}

#include<stdio.h>
#include<conio.h>
int main()
{
	int i;
	//print 1 to 100 using while loop
	while(i<=100)
	{
		printf("%d",i);
		i++;
	}
	
	//print 1 to 100 using do while
	do
	{
		printf("%d",i);
		i++;
	}
	while(i<=100);
	
	//print 1 to 100 using for loop
	for(i=1;i<100;i++)
	{
		printf("%d\n",i);
	}
	
	return 0;
}

//insertion operation in array.
#include<stdio.h>
#include<conio.h>
int main()
{
	int A[]={5,9,3,7,8};
	int n=5,item=10,k=3;
	int i=0,j=n;
	printf("\narray before operation...\n");
	for(i=0;i<n;i++)
	{
		printf("\nA[%d]=%d",i,A[i]);
	}
	n=n+1;
	while(j>=k)
	{
		A[j+1]=A[j];
		j=j-1;
	}
	A[k]=item;
	printf("\narray after insertion...\n");
	for(i=0;i<n;i++)
	{
		printf("\nA[%d]=%d",i,A[i]);
	}
	return 0;
}

How to make an easy calculator of four operations ( + , – , * , / ) by using switch case in c programming.

Codes are here….

Let see the codes

#include<stdio.h>
int main()
{
int a,b,c,result;
char operator;

printf("enter your choice\n1=+\n2=-\n3=*\n4=/\n");
scanf("%c",&operator);

printf("enter two numbers\n");
scanf("%d%d",&a,&b);

switch(operator)
    {
    case'1':
        result=a+b;
        break;
    case'2':
        result=a-b;
        break;
    case'3':
        result=a*b;
        break;
    case'4':
        result=a/b;
        break;
    default:
        printf("\nyou have entered blank option");
    }

printf("\nresult is =%d",result);   
getchar();
}

Output:

enter your choice
1=+
2=-
3=*
4=/
1
enter two numbers
10
20
result is =30
[Process completed - press Enter]

Let see in C Programming softwere….

Output: