Solutions to practice questions in Pointers

Display the address of an integer variable and one float variable.

#include <stdio.h>
int main(void){
int *poti;    // integer pointer 
float *potf;  // float pointer 

int i1=3;
poti=&i1; // Storing the address of i1  
printf("value of integer  : %d \n",*poti);

float  f1=5.6;
potf=&f1; // Storing the address of f1 
printf("value of Float   : %f \n",*potf);
return 0;
}

Declare a long variable and store its address in a pointer

#include <stdio.h>
int main(void){
long *pot_l;    // integer pointer 
long i=2147483647;
pot_l=&i; // Storing the address of i1  
printf("value of long  : : %ld \n",*pot_l);
return 0;
}

value of long  : : 2147483647

Declare a string variable and store its address in a pointer . Display the string along with its address.

#include <stdio.h>
int main(void){
char *potch;  // string  pointer 
char str[10]="plus2net";

potch=str;

while(*potch != '\0'){
printf("Address : %d , value :%c \n",potch,*potch);
potch++;
}
// to display the string in one line 
potch=str; // to point to first element
while(*potch != '\0'){
printf("%c",*potch);
potch++;
}
return 0;
}

Address : 6487552 , value :p
Address : 6487553 , value :l
Address : 6487554 , value :u
Address : 6487555 , value :s
Address : 6487556 , value :2
Address : 6487557 , value :n
Address : 6487558 , value :e
Address : 6487559 , value :t
plus2net

Find sum of two numbers using pointers

int *pot1,*pot2,sum, num1,num2;
 num1=100;
 num2=200;
 pot1=&num1;
 pot2=&num2;

 sum= *pot1 + *pot2;
      printf("sum =%d ",sum);

sum=300

Take two user input numbers and swap them using pointer and display.

   int num1,num2;
   int *pot1,*pot2,*pot3; // Pointer of an integer //
   
printf("Number 1 : ");
scanf("%d",&num1); // read the first number
printf("Number 2 : ");
scanf("%d",&num2); // read the second number 
   
pot1=&num1; // Store the address of first number 
pot2=&num2; // Store the address of second number 
pot3=pot2;  // Keep the address in another pointer
pot2=pot1;  // swap
pot1=pot3;  // swap

printf("value of Number 1 :  %d \n: ", *pot1);
printf("value of Number 2 : %d ", *pot2);

Pass two numbers to a function using pointer and display highest value.

#include <stdio.h>
int high(int *pot1,int *pot2){
if(*pot1>*pot2){ // check which is highest
 return *pot1;   // return value of pot1 if it is high
}else{
 return *pot2;  // return value of pot2 
}
}
int main(void){
int i=15,j=-15,*pot1,*pot2;

pot1=&i;  // store address of i in pointer pot1
pot2=&j;  // store address of j in pointer pot2

// pass the values to function high() and get the highest
printf("Highest  = %d \n",high(pot1,pot2));
return 0;
}

Highest = 15

Create one array and pass the array to a function by using pointer and then display all elements.

#include <stdio.h>
int array_disp(int *pot){
int k=0;
for(k=0;k<5;k++){
   printf("Element : %d \n", *pot);
   pot++;
}
}

int main(void){
int j[5]={1,2,3,4,5};
int *pot_main;
pot_main=&j[0];
array_disp(pot_main);
return 0;
}

Element : 1
Element : 2
Element : 3
Element : 4
Element : 5

In above question increase the value of elements by 2 inside the function and then display.

printf("Element : %d \n", *pot+2);

Display highest and lowest numbers in an array using pointer.

#include <stdio.h>
int main(void){
int i,num1[5]={-8,40,-5 ,6 ,7};
int *pot; // Pointer of an integer //
pot=&num1[0];   // assign address of num to pot //
int high=num1[0],low=num1[0];
 for(i=0;i<5;i++){
   if(high<*pot){
    high=*pot;
   }
   if(low>*pot){
    low=*pot;	
   }
 pot++;
 }
printf("Highest and lowest values are %d , %d ",high,low);
}

Highest and lowest values are 40 , -8

Sort an array using pointers

#include <stdio.h>
int main(void){
int num[]={-34,14,-11,15,0,-20};
int i=0,j=0;
int x=0;
int *pot=&num[0];
int *pot2=&num[0];
for(i=0;i<6;i++){
 pot=&num[i];
 for(j=i+1;j<6;j++){
  pot2=&num[j];
  // change below line to less than to get descending order 
  if(*pot>*pot2){ 
   x=*pot;
   *pot=*pot2;
   *pot2=x;
  }
 }
}
//// display the array elements//////
pot=&num[0];
for(i=0;i<6;i++){
 printf(" %d \n",*pot);
 pot++;
}  
}

 -34
 -20
 -11
 0
 14
 15

Write a program to print a string in revers using pointer

#include <stdio.h>
#include <string.h>
int main(void){

char *potch;  // Char pointer 
char str[30]="welcome to plus2net";
int j,length;
potch=&str[0]; 
length=strlen(str);

for(j=length-1;j>=0;j--){
printf("%c",*(potch+j));
}

return 0;
}

ten2sulp ot emoclew

Print the middle char of a string, if there are even numbers of chars then print the next char from the middle.

#include <stdio.h>
#include <string.h>
int main(void){

char *potch;  // Char pointer 
char str[30]="plus2net";
int j,length;
potch=&str[0]; 
length=strlen(str); // length of the string
printf("%c",*(potch+length/2));
return 0;
}

2

Create a function to receive an pointer of an array and a number to search. This function will return 1 if the number is found inside the array otherwise return 0.

#include <stdio.h>
int array_search(int *pot,int num1){
int k=0;
for(k=0;k<5;k++){
 if(num1==*pot){
   	return 1;
   	break; // No need to further continue
	}
 pot++;
}
return 0;
}

int main(void){
int j[5]={1,2,3,4,5}; // input array
int *pot_main;
int num1=7; // Number to be checked for presence
pot_main=&j[0];
if(array_search(pot_main,num1)==1){
printf("Yes available");
}else{
printf("Not available");	
}
return 0;
}