Dynamic Memory Allocation

calloc.c

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

int main(){

int i=0;
int *ptr;
int sum=0;

ptr=calloc(6 , sizeof(int));
printf("created memory of each block size %d \n",sizeof(ptr));

if( ptr==NULL){
    printf("somethings wrong with memory alloc\n");
}else{

for( i=0; i<6 ; i++){

    *(ptr+i)=i;
    sum +=*(ptr+i);//sum=1
    printf(" %d : value is %d\n",i,sum);

}

}
printf("sum of all values at each block = %d\n",sum);

free(ptr);//de-alloc
printf("memory was de-allocated");

return 0;
}

malloc.c

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

int main(){

int *ptr;

ptr= malloc(5* sizeof(*ptr));

if(ptr!= NULL){

    printf(" memory block created at %d\n",ptr);
    *(ptr+0)=10;
    *(ptr+1)=20;
    *(ptr+2)=30;
    *(ptr+3)=40;
    *(ptr+4)=50;
}else{

    printf(" cannot create ;");
}

int i=0;
for(i=0; i<6; i++){

    printf(" %d value is %d \n",i,*(ptr+i));

}
free(ptr);//de-alloc
printf("memory was de-allocated");

return 0;
}

realloc.c

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

int main(){

char *ptr;
ptr = (char*)malloc(10);
strcpy(ptr,"re");

printf(" %s , address at : %d\n",ptr,ptr);

ptr=(char *)realloc(ptr,2);
strcat(ptr,"Vijja");

printf("data is : %s , address = %u",ptr,ptr);


free(ptr);//de-alloc
printf("\nmemory was de-allocated");

return 0;
}