Programming Language C Tutorial – III (Programs on printf(), scanf(), Mathematical operators)

Programming Language C Tutorial – III

(Programs on printf(), scanf(), Mathematical operators)

Let us do the simple program to print given statement as output. Here we simply need to use printf() method to print statement.

We must include stdio.h (for print(), scanf()) and conio.h(for clrscr(), getch()) in every program.

// prog to print message  - heading of prog. (// - single line comment) #include<stdio.h>          - header /library files #include<conio.h> void main()                  - begining of pro by main() method. { clrscr();                      - to clear screen  printf("\nWelcome to learn C language"); getch();                    - to display output on screen }

Output – Welcome to learn C language

Following program is to print sum of two values. If we starting logic from beginning then we found that here we need three variables. Two variables are for input values and one is for output.

After beginning i.e. after main() method there is declaration part then write a input section followed by process section and finally print output.

Printf() function containing \n as a first argument for new line.

//prog to perform addition of two numbers #include<stdio.h> #include<conio.h> void main() {  int no1,no2,add;  clrscr(); //input  printf("\nEnter any two numbers");  scanf("%d%d",&no1,&no2); //process  add = no1 + no2;  //output  printf("\nAddition = %d",add);  getch(); }

Output – Enter any two numbers               12               23              Addition = 35

After you have studied above program then for better practice you should do programs for subtraction, multiplication and division.

How to create program for displaying mark sheet of student?

Now again think in logical order then you can find that here we need variables for roll no., name, marks of subjects, total and percentage. Then think about declaration of variables in appropriate data types, what is input? How is the process? And what will be the output?

//prog to print marksheet of student #include<stdio.h> #include<conio.h> void main() {  int rlno,s1,s2,s3,tot;  float per;  char sname[20];        //it accepts value 0 – 20 characters  clrscr();  printf("\nEnter roll no of student");  scanf("%d",&rlno);  printf("\nEnter name of student");  scanf("%s",&sname);  printf("\nEnter marks of 3 subjects");  scanf("%d%d%d",&s1,&s2,&s3);  //process  tot = s1 + s2 + s3;  per = (float)tot/3;  printf("\nTotal = %d\n",tot);  printf("\nPercent = %.2f",per);  //it will display per with 2 digit after decimal point  getch(); }

Output – Enter roll no of student               1               Enter name of student               Ram              Enter marks of 3 subjects              65              78              86             Total = 229            Percentage = 76.33

From above program you should create following programs

1. Item bill contains item code, item name, price, quantity, amount, discount(10% on amount) and net amount.
2. Payslip of employee conataing details empcode, empname, department, salary, annual salry, bonus(40% on annual salary) and gross salary.

Now, let us write a simple program to calculate area of circle. Here we should have two variables one for radius and other for area. Here we directly use standard value of pi.

// prog to calculate area of circle #include<stdio.h> #include<conio.h> void main() {  int rad;  float pi=3.14,area;  clrscr();  printf("\nEnter radius of circle");  scanf("%d",& rad);  area=pi*rad*rad;  printf("\nArea of circle=%.2f",area);  getch(); }

Output – Enter radius of circle               3              Area of circle = 28.26

You can be extend above program by adding formula of circumference. You should do this for good programming practice. You can be performing area of rectangle, area of square etc. programs.

Let us discuss small program having a different logic. Program to swap (interchanged) two integers. For this program we need three variables. Two for input and one more for swapping values. We have third variable temp because two variables already contained values.

Compare it with a example – If mother tell you to exchange the tin of sugar and tea then you should have a third empty container.

// prog to swap two integers #include<stdio.h> #include<conio.h> void main() {  int num1,num2,temp; clrscr();  printf("\nEnter two values for swaping");  scanf("%d%d",&num1, &num2); printf("\nBefore swaping num1=%d \t num2=%d",num1,num2)  temp = num1; num1 = num2; num2 = temp;  printf("\nAfter swaping num1=%d \t num2=%d",num1,num2);  getch(); }

Output – Enter two values for swaping               300               900              Before swaping num1=300 num2=900              After swaping num1=900 num2=300