This page contains a collection examples on basic concepts of C programming like: loops, functions, pointers, structures etc.

Feel free to use the source code on your system.


C program for lowwer case of a string using library functions
#include<stdio.h>
#include<string.h>
#include<conio.h>

void main()
{
 char str1[30];
 clrscr();
 printf("\nEnter a string:");
 scanf("%s",str1);
 strlwr(str1);
 printf("\nYou have enter string: %s",str1);
 getch();
}
C program for upper case of a string using library functions
#include<stdio.h>
#include<string.h>
#include<conio.h>

void main()
{
 char str1[30];
 clrscr();
 printf("\nEnter a string:");
 scanf("%s",str1);
 strupr(str1);
 printf("\nYou have enter string: %s",str1);
 getch();
}

C program for concatenation of two string using library functions
#include<stdio.h>
#include<string.h>
#include<conio.h>

void main()
{
 char str1[30],str2[30];
 clrscr();
 printf("\nEnter a string 1:");
 scanf("%s",str1);
 printf("\nEnter a string 2:");
 scanf("%s",str2);
 strcat(str1,str2);
 printf("\nYou have enter string: %s",str1);
 getch();
}
C program for reversing a string using library functions
#include<stdio.h>
#include<string.h>
#include<conio.h>

void main()
{
 char str1[30];
 clrscr();
 printf("\nEnter a string:");
 scanf("%s",str1);
 strrev(str1);
 printf("\nYou have enter string: %s",str1);
 getch();
}
C program for copying a string using library function
#include<stdio.h>
#include<string.h>
#include<conio.h>

void main()
{
 char str1[30],str2[30];
 clrscr();
 printf("\nEnter a string:");
 scanf("%s",str1);
 strcpy(str2,str1);
 printf("\nYou have enter string: %s",str2);
 getch();
}
C program for writing Alphabets in C using asterik(*)
#include<stdio.h>
#include<conio.h>

void main()
{
        int j,i;
 clrscr();
 for(i=1;i<=7;i++)
 {
  for(j=1;j<=56;j++)
  {

if(j==1||i==1&&j==2||i==1&&j==3||i==1&&j==4||i==7&&j==4||i==7&&j==2||i==7&&j==3||i==7&&j==4||i==6&&j==4||i==2&&j==4||j==7||j==10||i==1&&j==8||i==1&&j==9||i==7&&j==8||i==7&&j==9||j==13||i==1&&j==14||i==1&&j==15||i==7&&j==14||i==7&&j==15||j==16&&i==2||j==16&&i==3||j==16&&i==4||j==16&&i==5||j==16&&i==6||j==19||i==1&&j==20||i==1&&j==21||i==1&&j==22||i==4&&j==20||i==4&&j==21||i==4&&j==22||i==7&&j==20||i==7&&j==21||i==7&&j==22||i==2&&j==27||i==2&&j==29||i==3&&j==28||j==30||j==26||j==33||j==36||i==1&&j==34||i==1&&j==35||i==7&&j==34||j==45||i==7&&j==35||j==39||i==1&&j==40||i==1&&j==41||i==7&&j==40||i==7&&j==41||j==42&&i==2||j==42&&i==3||j==42&&i==4||j==42&&i==5||j==42&&i==6||j==19||i==1&&j==46||i==1&&j==47||i==1&&j==48||i==4&&j==46||i==4&&j==47||i==4&&j==48||i==7&&j==46||i==7&&j==47||i==7&&j==48||j==55||i==1&&j==52||i==1&&j==53||i==1&&j==54||i==2&&j==52||i==4&&j==54||i==4&&j==56)

  {
   printf("*");
  }
  else
  {
   printf(" ");
  }
  }
 printf("\n");
 }

        getch();
}
C Program for sum of columns of the matrix
#include<stdio.h>
#include<conio.h>

void main()
{
 int i,j,a[3][3],sum1=0,sum2=0,sum3=0;
 clrscr();
 printf("\nEnter the matrix");
 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   scanf("%d",&a[i][j]);
  }
 }
 printf("\nYou have entered matrix:\n");
 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   printf("\t%d",a[i][j]);
  }
  printf("\n");
 }
   for(i=0;i<3;i++)
   {
  for(j=0;j<3;j++)
  {
   if(j==0)
    sum1=a[i][j]+sum1;
   else if(j==1)
    sum2=a[i][j]+sum2;
   else if(j==2)
    sum3=a[i][j]+sum3;
  }
   }
   printf("\nSum1=%d\nSum2=%d\nSum3=%d",sum1,sum2,sum3);
   getch();
}
C program for displaying UNIT matrix.
 
#include<stdio.h>
#include<conio.h>

void main()
{
 int i,j,a[3][3];
 clrscr();
 printf("\nEnter the matrix:\n\n");

 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
    if(i==j)
    {
    a[i][j]=1;
    printf("%d\t",a[i][j]);
    }
    else
    {
     a[i][j]=0;
     printf("%d\t",a[i][j]);
    }

  }
  printf("\n");
 }
 getch();
}
C program for transposing of matrix.
#include<stdio.h>
#include<conio.h>

void main()
{
 int i,j,a[3][3];
 clrscr();
 printf("\nEnter the matrix:");
 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   scanf("%d",&a[i][j]);
  }
 }
 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   printf("%d\t",a[i][j]);
  }
  printf("\n");
 }
 printf("\n\n");
 printf("\natfer transpose\n");
 for(j=0;j<3;j++)
 {
  for(i=0;i<3;i++)
  {
   printf("%d\t",a[i][j]);
  }
  printf("\n");
 }
 getch();
}
C program for addition of two matrix
void main()
{
 int i,j,a[3][3],b[3][3],add[3][3];

 clrscr();
 printf("\nEnter the matrix:");
 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   scanf("%d",&a[i][j]);
  }
 }
 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   scanf("%d",&b[i][j]);
  }
 }

 printf("\n\n");

 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   printf("%d\t",a[i][j]);
  }
  printf("\n");
 }

 printf("\n\n");

 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   printf("%d\t",b[i][j]);
  }
  printf("\n");
 }

 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   add[i][j]=a[i][j]+b[i][j];
  }
 }
 printf("\n\n");

 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   printf("%d\t",add[i][j]);
  }
  printf("\n");
 }
 getch();
}
C program for displaying matrix
#include<stdio.h>
#include<conio.h>

void main()
{
 int i,j,a[3][3];
 clrscr();
 printf("\nEnter the matrix:");
 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   scanf("%d",&a[i][j]);
  }
 }

 for(i=0;i<3;i++)
 {
  for(j=0;j<3;j++)
  {
   printf("%d\t",a[i][j]);
  }
  printf("\n");
 }
 getch();
}
C program for sorting (BUBBLE SORT)
#include<stdio.h>
#include<conio.h>

void main()
{
 int i,j,temp,a[10];
 clrscr();
 printf("\nEnter the numbers: ");
 for(i=0;i<10;i++)
  scanf("%d",&a[i]);
 printf("\nBefore sorting- ");
 for(i=0;i<10;i++)
  printf("\t%d",a[i]);
 for(i=0;i<10;i++)
 {
  for(j=i+1;j<10;j++)
  {
   if(a[i]>a[j])
   {
    temp=a[i];
    a[i]=a[j];
    a[j]=temp;
   }
  }
 }
 printf("\nAfter sorting: ");
 for(i=0;i<10;i++)
  printf("\t%d",a[i]);

 getch();
}

C program for finding sum of n numbers.
//find  sum of n no

#include<stdio.h>
#include<conio.h>

void main()
{
 int sum=0,n,i;
 printf("\nEnter n number");
 scanf("%d",&n);
 for(i=0;i<n;i++)
  sum=sum+i;
 printf("Sum of n number - %d",sum);
 getch();
}
C program for sum of 10 numbers.
#include<stdio.h>
#include<conio.h>

void main()
{
 int sum=0,i;
 clrscr();
 for(i=0;i<10;i++)
  sum=sum+i;
 printf("sum of ten no- %d",sum);
 getch();
}


 
C program for displaying 100 even numbers.
#include<stdio.h>
#include<coonio.h>

void main()
{
 int num=0,i;
 clrscr();
 for(i=0;i<=100;i++)
 {       if(num%2==0)
  {
   printf("\t%d",num);
  }
  num++;
 }
 getch();
}
C program for displaying day
// C program displaying day

#include<stdio.h>
#include<conio.h>

void main()
{
 int a;
 clrscr();
 printf("Enter a number between 1-7 for displaying day!!!-");
 scanf("%d",&a);
 if(a==1)
  printf("\nThe day is monday!!!");
 else if(a==2)
  printf("\nThe day is tuesday!!!");
 else if(a==3)
  printf("\nThe day is wednesday!!!");
 else if(a==4)
  printf("\nThe day is thursday!!!");
 else if(a==5)
  printf("\nThe day is friday!!!");
 else if(a==6)
  printf("\nThe day is saturday!!!");
 else if(a==7)
  printf("\nThe day is sunday!!!");
 getch();
}
C program for find greater number
//To find Greater number

#include<stdio.h>
#include<conio.h>

void main()
{
 int a,b,c;
 clrscr();
 printf("\nEnter three numbers- ");
 scanf("%d%d%d",&a,&b,&c);
 if(a>b && a>c)
  printf("\n%d is greater number!!!",a);
 else if(b>a && b>c)
  printf("\n%d is greater number!!!",b);
 else
  printf("\n%d is greater number!!!",c);
 getch();
}
C program for find vowel or consonant
//to find vowel our consonant

#include<stdio.h>
#include<conio.h>

void main()
{
char ch;
clrscr();
printf("\nEnter a Alphabet- ");
scanf("%c",&ch);
if(ch=='a'|| ch=='e'|| ch=='i'|| ch=='o'|| ch=='u')
printf("\nYou have entered a vowel!!!");
else if(ch=='A'|| ch=='E'|| ch=='I'|| ch=='O'|| ch=='U')
printf("\nYou have entered a vowel!!!");
else
printf("\nYou have entered a consonant!!!");
getch();
} 
C program for sum of first and last digit of four digit number
//Addition of four digit numbe

#include<stdio.h>
#include<conio.h>

void main()
{
 int sum=0,rem,num;
 clrscr();
 printf("\nEnter a four digit number- ");
 scanf("%d",&num);

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 printf("\nAddition of four digit number- %d",sum);
 getch();

}
C program to reverse a four digit number
void main()
{
 int num,rev=0,rem;
 clrscr();
 printf("\nEnter a four digit number- ");
 scanf("%d",&num);
 rem=num%10;
 rev=rev*10+rem;
 num=num/10;

 rem=num%10;
 rev=rev*10+rem;
 num=num/10;

 rem=num%10;
 rev=rev*10+rem;
 num=num/10;

 rem=num%10;
 rev=rev*10+rem;
 num=num/10;

 printf("\nThe reversed number- %d",rev);
 getch();
}
C program for finding area of triangle
//C program to find area of triangle

#include<stdio.h>
#include<conio.h>
#define half 0.5                  

void main()
{
 int length,breadth;
 float area;
 clrscr();
 printf("\nEnter the Length- ");
 scanf("%d",&length);
 printf("\nEnter the Breadth- ");
 scanf("%d",&breadth);
 area=half*length*breadth;
 printf("\nArea of triangle- %.3f",area);
 getch();
}
C Program for swaping two numbers without using third vaariable
//swaping two number without using third variable

#include<stdio.h>
#include<conio.h>

void main()
{
 int a,b,temp;
 clrscr();
 printf("\nEnter value of A- ");
 scanf("%d",&a);
 printf("\nEnter value of B- ");
 scanf("%d",&b);
 a=a+b;
 b=a-b;
 a=a-b;
 printf("\nAter Swap- ");
 printf("A=%d\t\tB=%d",a,b);
 getch();
}
C Program for find Area
void main()
{      
        int r;
 float area;
 clrscr();
 printf("\nEnter a number to find the Area- ");
 scanf("%d",&r);
 area=pie*r*r;
 printf("\nArea= %.2f",area);
 getch();
}
C Program for swaping two variable using third variable
#include<stdio.h>
#include<conio.h>
void main()
{
 int a,b,temp;
 temp=0;
 clrscr();
 printf("\nEnter number A: ");
 scanf("%d",&a);
 printf("\nEnter number B: ");
 scanf("%d",&b);
 temp=a;
 a=b;
 b=temp;
 printf("\nAfter SWAP:");
 printf("A=%d\t\tB=%d",a,b);
 getch();
}
C Program for displaying discount
#include<stdio.h> 
#include<conio.h>

void main() 
{ 
int price,amt,no,disc=0; 
clrscr(); 
printf("Enter the amount you have purchased- "); 
scanf("%d",&amt); 
printf("Enter the no: "); 
scanf("%d",&no); 
price=amt*no; 
if(price>2000) 
{ 
disc=price-price*40/100; 
printf("\nYou have got discount of rupees-%d ",disc); 
} 
else if(price<1000) 
{ 
disc=price-price*30/100; 
printf("\nYou have got discount of rupees-%d ",disc); 
} 

getch(); 
}
C Program for printing a number n time
#include<stdio.h>
#include<conio.h>

void main() 
{ 
int num,i=1; 
clrscr(); 
printf("Enter a number-"); 
scanf("%d",&num); 
while(i<=num) 
{ 
printf("\n%d",num); 
i++; 
}
getch();
}

C program for displaying 1 - 10 table.
//display 1-10 table

#include<stdio.h>
#include<conio.h>

void main()
{
 int num=1,i,j;
 clrscr();
 for(i=1;i<11;i++)
 {
  for(j=1;j<=10;j++)
   printf("\n%d X %d = %d",num,j,num*j);
  printf("\t");
  num++;

 }
 getch();
}


C program for displaying pattern
//c program for displaying pattern

#include<stdio.h>
#include<conio.h>

void main()
{
 int j,i;
 clrscr();
 for(i=0;i<=4;i++)
 {
  for(j=0;j<=4;j++)
  {
  if(i==0||i==4||j==0||j==4||i==2&&j==2)
  {
   printf("*");
  }
  else
   printf(" ");
  }
 printf("\n");
 }

 getch();
}
C program for displaying elements in array
 
//C program for displaying elements in array

#include<stdio.h>
#include<conio.h>

void main()
{
 int j,i;
 clrscr();
 printf("Enter the array- ");
 for(i=0;i<10;i++)
  scanf("%d",&a[i]);
 printf("\nThe array  element -\n ");
 for(i=0;i<10;i++)
  printf("%d\t",a[i]);
 getch();
}
C program for finding out the leap year
 
//to find out the leap year

#include<stdio.h>
#include<conio.h>

void main()
{
 int year;
 clrscr();
 printf("\nEnter a year- ");
 scanf("%d",&year);
 if(year%4==0 && year%100==0 || year%400==0)
  printf("\nThe year you have enter is leap year!!!");
 else if(year%4!=0 && year%100!=0 || year%400!=0)
  printf("\nThe year you have enter is not leap year!!!");
 getch();
}
C program for addition of four digit number
//Addition of four digit number

#include<stdio.h>
#include<conio.h>

void main()
{
 int sum=0,rem,num;
 clrscr();
 printf("\nEnter a four digit number- ");
 scanf("%d",&num);

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 rem=num%10;
 sum=sum+rem;
 num=num/10;

 printf("\nAddition of four digit number- %d",sum);
 getch();

}