Basic Structure of C-Program

Basic Structure of C-Program

Structure of c-programs

Documentation Section • The Documentation Section consists of set of comment lines giving the  Name of the program  The author  Other Details which the programmer would like to use later  Syntax /* Multiple Comment lines *\ // Single Comment line  Example /* c –program to find gcd and lcm of two numbers using Euclid's Algorithm *\ // Welcome to C

Link Section • The link section provides instruction to the complier to link functions from system library • Syntax #include Header files stdio– Standard Input /Output conio– Console input/Output, math- contains mathematical functions like (cos(), sin(), sqrt(), abs()) • Example #include #include

Definition Section • This section is used to define symbolic constants • Syntax:#define symbolic-name constant-value • Example:#define pi 3.142 #define maxmarks 100 #define minmarks 35

Global declaration Section • In C There are two types of declarations 1.Local variable declaration 2. Global variable Declaration • Global variables are declared out side the main function • Local variables are declared inside the main function

Variable declaration • Syntax:data-type variable-name; Ex:int a,x; float b,c; char name;

Main() function • C-program should have at least one main() function • Form:main() { local variables declaration computation part logic part }

Reading data from input device (keyboard) • scanf() function is used to read the data from standard input device • Syntax:scanf(“format specifier”,&var1,&var2-----,&varn)

• Example:scanf(“%d”,&a) for int data-type scanf(“%f”,&b) for float data-type

Print data or variable • printf() is used to print the variable or data • Syntax:printf(“ message -format specifier”,var1,var2-----,varn)

• Example:printf(“Welcome to c”); int a=10; printf(“value of a=%d”,a);

Arithmetic operators

C op

Write a c-program to find sum of two numbers

/* c-program to find sum of two numbers *\ #include //link section #include main() { int a,b,sum; // local variable declaration clrscr(); printf("enter two numbers \n"); scanf("%d%d",&a,&b); // reading input from std i/p sum=a+b; //computation part printf("sum of two numbers=%d",sum); //ouput getch(); }

Write a c-program to find Area of a Circle

/* c-program to find Area of a circle *\ #include #include #define pi 3.142 // definition section main() { float r,area; clrscr(); printf("enter the radius value\n"); scanf("%f",&r); area=pi*r*r; printf("area of a circle=%f",area); getch(); }

Write a c-program to evaluate following expressions • Area=∏r2 +2∏rh • Torque= (2m1m2/(m1+m2))*g • Side=sqrt(a2+b2+2abcos(x)) • Energy= mass [(acceleration*ht)+(vel)2/2]

Write a c-program to convert number of days to a measure of time given in years, weeks and days Example:375 days is equal to 1 year 1 week 3 days

# include #include #define DAYSINWEEK 7 main() { int ndays, year, week, days; clrscr(); printf("Enter the number of days\n"); scanf("%d",&ndays); year = ndays/365; week = (ndays % 365)/DAYSINWEEK; days = (ndays%365) % DAYSINWEEK; printf ("%d is equivalent to %d years, %d weeks and %d days\n", ndays, year, week, days); getch(); }

Write a c-program to compute the surface area and volume of the cube • surfArea=6.0*side*side • Volume=side3

#include #include #include main() { float side, surfArea, volume; clrscr(); printf("Enter the length of a side\n"); scanf("%f", &side); surfArea = 6.0 * side * side; volume = pow (side, 3); printf("Surface area =%f and Volume=%f", surfArea, volume); getch(); }

Write a C-Program To Accept Student Roll No, Marks in 3 Subjects and Calculate Total, Average and Print it.

# include # include main() { int r,b,c,d, tot, avg; clrscr(); printf (“ENTER STUDENT RNO ; “); scanf (“%d”,&r); printf(“ENTER FIRST SUBJECT MARKS ;”); scanf(“%d”,&b); printf(“ENTER SECOND SUBJECT MARKS;”); scanf(“%d”,&c); printf(“ENTER THIRD SUBJECT MARKS ;”); scanf(“%d”,&d); tot=b+c+d; avg=tot/3; printf(“\t STUDENT RNO ; %d “,r); printf(“\t FIRST SUBJECT MARKS ;%d “,b); printf(“\t SECOND SUBJECT MARKS ;%d “,C); printf(“\t THIRD SUBJECT MARKS ;%d “,d); printf(“\t AVERAGE MARKS ; %d”, avg); getch(); }

Write a C-Program to accept a three digit number and print the sum of individual digits.

# include # include main( ) { int a,b,c,n, sum; clrscr( ); printf (“ Enter a Three Digit Number:“); scanf (“%d”,&n); a=n/100; b=( (n%100)/10); c=n%10; sum=a+b+c; printf (“ Sum of Individual Digits of Given Numbers is %d”, Sum); getch( ); }