Switch case examples in C

//1. Chceck input number is 1,2 or 3
#include<stdio.h>

int main()
{

      int n;

      printf("Enter a Number:");
     scanf("%d",&n);

   
     switch( n )
     {
        case 1 : printf( "Your number is 1\n" );
                   break;
        case 2 : printf( "Your number is 2\n" );
                   break;
        case 3 : printf( "Your number is 3\n" );
                   break;
        default  : printf( "Try Again\n" );
                   break;
     }

return 0;
}
==============================================================

===============================================================
//2.Check user input letter is vowel or not
#include<stdio.h>

int main()
{

      char ch;

      printf("Enter the Vowel (In Capital Letter):");
     scanf("%c",&ch);

   
     switch( ch )
     {
        case 'A' : printf( "Your Character Is A\n" );
                   break;
        case 'E' : printf( "Your Character Is E\n" );
                   break;
        case 'I' : printf( "Your Character Is I\n" );
                   break;
        case 'O' : printf( "Your Character Is O\n" );
                   break;
        case 'U' : printf( "Your Character Is U\n" );
                   break;
        default  : printf( "Your Character is Not Vowel.Otherwise Not a Capital Letter\n" );
                   break;
     }

return 0;
}

===============================================================
//3.check week name
#include<stdio.h>

int main()
{

      int day;

      printf("Enter a number:");
     scanf("%d",&day);

     switch (day)
  {
   case 1 : printf("Sunday\n");
            break;
   case 2 : printf("Monday\n");
            break;
   case 3 : printf("Tuesday\n");
            break;
   case 4 : printf("Wednesday\n");
            break;
   case 5 : printf("Thursday\n");
            break;
   case 6 : printf("Friday\n");
            break;
   case 7 : printf("Saturday\n");
            break;
  default : cout << "Not an allowable day number";
            break;
  }

return 0;
}

===============================================================
//check color
#include <stdio.h>

int main() {
    int color = 1;
    printf("Please choose a color(1: red,2: green,3: blue):\n");
    scanf("%d", &color);

    switch (color) {
        case 1:
            printf("you chose red color\n");
            break;
        case 2:
            printf("you chose green color\n");
            break;
        case 3:
            printf("you chose blue color\n");
            break;
        default:
            printf("you did not choose any color\n");
    }
    return 0;
}
=============================================================
//5.check student grade

#include <stdio.h>

main()
{
     int  Grade = 'B';

     switch( Grade )
     {
        case 'A' : printf( "Excellent\n" );
                   break;
        case 'B' : printf( "Good\n" );
                   break;
        case 'C' : printf( "OK\n" );
                   break;
        case 'D' : printf( "Mmmmm....\n" );
                   break;
        case 'F' : printf( "You must do better than this\n" );
                   break;
        default  : printf( "What is your grade anyway?\n" );
                   break;
     }
}

=============================================================

while example in C

#include <stdio.h>
#include <stdlib.h>

//print "Hello" n times

int main()
{
    int number,i=1;

    scanf("%d",&number);

    while ( i <= number )
    {
       printf("Hello\n");
       i = i+1;
    }

    return 0;
}
==========================

==========================

#include <stdio.h>
#include <stdlib.h>

//print value of a variable n times

int main()
{
    int number,i=1;

    scanf("%d",&number);

    while ( i <= number )
    {
       printf("value of i is %d\n", i );
       i = i+1;
    }

    return 0;
}


========================

#include <stdio.h>
#include <stdlib.h>

//Calculate sum of n number

int main()
{
    int number,sum=0,i = 1;

    scanf("%d",&number);

    while ( i <= number )
    {
       printf("%d,",i);
       sum = sum + i;
       i = i+1;
    }

    printf("\nSum :%d\n",sum);

    return 0;
}

==========================

#include <stdio.h>
#include <stdlib.h>

//Calculate sum of n odd number

int main()
{
    int number,sum=0,i = 1;

    scanf("%d",&number);

    while ( i <= number )
    {
       printf("%d,",i);
       sum = sum + i;
       i = i+2;
    }

    printf("\nSum :%d\n",sum);

    return 0;
}

==========================
#include <stdio.h>
#include <stdlib.h>

//Calculate sum of n even number

int main()
{
    int number,sum=0,i = 2;

    scanf("%d",&number);

    printf("Calculate sum of even number between 2 to %d\n",number);

    while ( i <= number )
    {
       printf("%d,",i);
       sum = sum + i;
       i = i+2;
    }

    printf("\nSum :%d\n",sum);

    return 0;
}

If-Else Example

#include <stdio.h>
#include <stdlib.h>

//checking student passed or failed in exam
int main()
{
    int mark;
    scanf("%d",&mark);
    if(mark>=50)
        printf("You are passed");
    else
        printf("You are failed");

    return 0;
}

=====================================
#include <stdio.h>
#include <stdlib.h>

//checking student grade
int main()
{
    int mark;
    scanf("%d",&mark);
    if(mark>=80)
        printf("Grade : A+");
    else if(mark>=70)
        printf("Grade: A");
    else if(mark>=60)
        printf("Grade: A-");
    else if(mark>=50)
        printf("Grade: B");
    else if(mark>=40)
        printf("Grade: B-");
    else
        printf("Grade: Fail");

    return 0;
}

======================================

#include <stdio.h>
#include <stdlib.h>

//check a number is even or odd

int main()
{
    int number;
    scanf("%d",&number);
    if(number == 0)
        printf("Given number is zero");
    else if(number%2==0)
        printf("%d is a even number",number);
    else
        printf("%d is a odd number",number);
    return 0;
}

==========================================

==========================================

#include <stdio.h>
#include <stdlib.h>

//check a number is positive or negative

int main()
{
    int number;
    scanf("%d",&number);
    if(number == 0)
        printf("Given number is zero");
    else if(number>0)
        printf("%d is a positive number",number);
    else
        printf("%d is a negative number",number);
    return 0;
}

===========================================
#include <stdio.h>
#include <stdlib.h>

//voting age check

int main()
{
    int age;
    printf("Enter Your Age :");
    scanf("%d",&age);
    if(age>=18)
    {
         printf("you can vote");
    }
    else
    {
         printf("you are not Eligible for voting");
    }
    return 0;
}

For Loop Example

#include <stdio.h>
#include <stdlib.h>

//print a statement n times using for

int main()
{
    int number,sum=0,i;

    scanf("%d",&number);

    for(i = 1;i<=number;i++)
    {
         printf("Welcome\n");
    }


    return 0;
}

======================================

#include <stdio.h>
#include <stdlib.h>


//print a variable value n times

int main()
{
    int number,sum=0,i;

    scanf("%d",&number);

    for(i = 1;i<=number;i++)
    {
         printf("Value of i :%d\n",i);
    }


    return 0;
}

=======================================



=======================================

#include <stdio.h>
#include <stdlib.h>


//print  loop variable value

int main()
{
    int number,sum=0,i;

    scanf("%d",&number);

    for(i=number;i>=1;i=i-1)
    {
         printf("value of i is %d\n",i);
    }


    return 0;
}

=======================================

#include <stdio.h>
#include <stdlib.h>


//Calculate sum of n number

int main()
{
    int number,sum=0,i;

    scanf("%d",&number);

    for(i = 1;i<=number;i++)
    {
        sum = sum + i;
    }

    printf("Sum :%d\n",sum);

    return 0;
}


=========================================

#include <stdio.h>
#include <stdlib.h>


//Calculate sum of n even number

int main()
{
    int number,sum=0,i;

    scanf("%d",&number);

    for(i = 2;i<=number;i = i+2)
    {

        printf("%d,",i);
        sum = sum + i;
    }

    printf("\nTotal Sum:%d\n",sum);

    return 0;
}

=========================================

#include <stdio.h>
#include <stdlib.h>


//Calculate sum of n odd number

int main()
{
    int number,sum=0,i;

    scanf("%d",&number);

    for(i = 1;i<=number;i = i+2)
    {

        printf("%d,",i);
        sum = sum + i;
    }

    printf("\nTotal Sum:%d\n",sum);

    return 0;
}

Write a program to find the sum of first n natural numbers where n is entered by user (For-Loop)

#include <stdio.h>
#include <stdlib.h>


int main()
{
    int number, sum = 0, i;
    printf("Enter a number: ");
    scanf("%d",&number);

    for(i=1;i<=number;i=i+1)
    {
        printf("%d(sum)",sum);
        sum = sum + i;
        printf(" + %d(i) = %d(sum)\n",i,sum);

    }
    printf("Sum: %d",sum);


    return 0;
}

Output:

check whether a number entered by user is even or odd in C using If-Else

#include <stdio.h>
#include <stdlib.h>

//Write a C program to check whether a number entered by user is even or odd
int main()
{
    int number;
    printf("Enter a number :");
    scanf("%d",&number);

    if(number%2==0)
        printf("%d is a even number",number);
    else
        printf("%d is a odd number",number);


    return 0;
}

Output:

Checking a number is postive or negative in C using If-Else

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int number;
    //number = 50;

    scanf("%d",&number);

    if(number == 0)
        printf("Given number is %d",number);
    else if(number>0)
        printf("%d is a Positive number",number);
    else
        printf("%d is a Negative number",number);

    return 0;
}

Output:

ACM Problem Solution 10696 - f91

problem

#include<stdio.h>

long int result(long int n)
{
  if(n<=100)
    return(result(result(n+11)));
  else if(n>=101)
    return(n-10);

}
int main()
{
long int n,x;
while(scanf("%ld",&n)==1)
{
    if(n==0)
        break;
    x=result(n);
    printf("f91(%ld) = %ld\n",n,x);

}
return 0;

}

ACM Problem Solution : 10035 Primary Arithmetic

problem
#include <stdio.h>
#include<string.h>>
int main() {
char a[100],b[100];
int lena,lenb,x,y,num1,num2,cry,sum,i,j;
while(scanf("%s%s",&a,&b)==2)
{
    if(a[0]=='0'&&b[0]=='0')
        break;
    lena=strlen(a);
    lenb=strlen(b);
    x=0;
    cry=0;
    for(i=lena-1,j=lenb-1;i>=0||j>=0;j--,i--)
    {
     if(i>=0)
     num1=a[i]-48;
    else num1=0;
    if(j>=0)
     num2=b[j]-48;
     else num2=0;
     sum=num1+num2+x;
        if(sum>9)
        {
        cry++;
        x=sum/10;

        }
        else x=0;
    }
    if(cry==0)
        printf("No carry operation.\n");
    else if(cry==1)
    printf("%d carry operation.\n",cry);

    else
    printf("%d carry operations.\n",cry);

}

return 0;

}

Find topological sort of directed graph

#include<stdio.h>

int vertex,indegree1[50],strtop[50];
int graph[50][50];
void topo(int vertex);

int main()
{


    int i,j,edge,p,x,y,kk,ff,rr;
    printf("Enter the Number of Vertex : ");
    scanf("%d",&vertex);
    printf("\n");
    printf("Enter the Number of Edge : ");
    scanf("%d",&edge);
    printf("\n");
    for(ff=1;ff<=vertex;ff++)
    for(rr=1;rr<=vertex;rr++)
        graph[ff][rr]=0;
    for(i=1;i<=edge;i++)
    {
    scanf("%d%d",&x,&y);
    graph[x][y]=1;

    }
    for(kk=1;kk<=vertex;kk++)
    {    indegree1[kk]=0;
    strtop[kk]=0;
    }
    printf("\n");
    for(i=1;i<=vertex;i++)
      for(j=1;j<=vertex;j++)
          if(graph[j][i]==1)
            indegree1[i]++;
    topo(vertex);
    return 0;
}
void topo(int vertex)
{
    int l,p,xx,node,top=0,d=0,flag=0,pp;
    for(l=1;l<=vertex;l++)
    {
        if(indegree1[l]==0)
        {
              strtop[++top]=l;
              flag=1;
        }

    }
    if(flag==0)
    {    printf("Topological sort is not possible\n");

    }
    else
    {

        while(d!=vertex)
        {
        node=strtop[++d];
        for(xx=1;xx<=vertex;xx++)
            if(graph[node][xx]==1)
            {
                indegree1[xx]=indegree1[xx]-1;
                if(indegree1[xx]==0)
                    strtop[++top]=xx;
            }


        }
        printf("\nAfter topological sort : \n");
        for(pp=1;pp<=vertex;pp++)
            printf("%d ",strtop[pp]);
        printf("\n");

    }

}