1. Integer Pointer

#include <stdio.h>

int main() {
    int a = 10;
    int *p = &a;

    printf("%d\n", *p);
    return 0;
}

2. Float Pointer

#include <stdio.h>

int main() {
    float a = 5.5;
    float *p = &a;

    printf("%.2f\n", *p);
    return 0;
}

3. Double Pointer

#include <stdio.h>

int main() {
    double a = 12.456;
    double *p = &a;

    printf("%lf\n", *p);
    return 0;
}

4. Character Pointer

#include <stdio.h>

int main() {
    char ch = 'A';
    char *p = &ch;

    printf("%c\n", *p);
    return 0;
}

5. Void Pointer

#include <stdio.h>

int main() {
    int a = 20;
    void *p = &a;

    printf("%d\n", *(int*)p);
    return 0;
}

6. NULL Pointer

#include <stdio.h>

int main() {
    int *p = NULL;

    printf("%p\n", p);
    return 0;
}

7. Wild Pointer

#include <stdio.h>

int main() {
    int *p;

    return 0;
}

8. Dangling Pointer

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

int main() {
    int *p = (int*)malloc(sizeof(int));
    *p = 50;

    free(p);
    return 0;
}

9. Pointer to Pointer

#include <stdio.h>

int main() {
    int a = 15;
    int *p = &a;
    int **q = &p;

    printf("%d\n", **q);
    return 0;
}

10. Array Pointer

#include <stdio.h>

int main() {
    int arr[3] = {1,2,3};
    int *p = arr;

    for(int i=0;i<3;i++)
        printf("%d ", *(p+i));

    return 0;
}

11. Function Pointer

#include <stdio.h>

int add(int a, int b) {
    return a + b;
}

int main() {
    int (*p)(int,int) = add;

    printf("%d\n", p(2,3));
    return 0;
}

1. Pointer Expressions and Operations

#include <stdio.h>

int main() {
    int a = 10, b = 20;
    int *p1 = &a;
    int *p2 = &b;

    printf("%d\n", *p1);
    printf("%d\n", *p2);

    *p1 = 50;
    printf("%d\n", a);

    p1++;
    printf("%p\n", p1);

    p1--;
    printf("%p\n", p1);

    return 0;
}

2. Pointer with Array

#include <stdio.h>

int main() {
    int arr[5] = {10,20,30,40,50};
    int *p = arr;

    for(int i=0;i<5;i++) {
        printf("%d ", *(p+i));
    }

    printf("\n");

    for(int i=0;i<5;i++) {
        printf("%d ", *(arr+i));
    }

    return 0;
}

3. Dynamic Memory Allocation using malloc()

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

int main() {
    int n;
    scanf("%d",&n);

    int *p = (int*)malloc(n * sizeof(int));

    for(int i=0;i<n;i++)
        p[i] = i + 1;

    for(int i=0;i<n;i++)
        printf("%d ", p[i]);

    free(p);
    return 0;
}

4. Dynamic Memory Allocation using calloc()

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

int main() {
    int n = 5;

    int *p = (int*)calloc(n, sizeof(int));

    for(int i=0;i<n;i++)
        printf("%d ", p[i]);

    free(p);
    return 0;
}

5. Dynamic Memory Allocation using realloc()

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

int main() {
    int *p = (int*)malloc(3 * sizeof(int));

    for(int i=0;i<3;i++)
        p[i] = i + 1;

    p = (int*)realloc(p, 5 * sizeof(int));

    for(int i=3;i<5;i++)
        p[i] = i + 1;

    for(int i=0;i<5;i++)
        printf("%d ", p[i]);

    free(p);
    return 0;
}

6. String Input and Output

#include <stdio.h>

int main() {
    char str[50];

    scanf("%s", str);
    printf("%s\n", str);

    return 0;
}

7. String Length

#include <stdio.h>
#include <string.h>

int main() {
    char str[] = "Praful";

    printf("%lu\n", strlen(str));

    return 0;
}

8. String Copy

#include <stdio.h>
#include <string.h>

int main() {
    char s1[] = "Hello";
    char s2[20];

    strcpy(s2, s1);

    printf("%s\n", s2);

    return 0;
}

9. String Concatenation

#include <stdio.h>
#include <string.h>

int main() {
    char s1[30] = "Hello ";
    char s2[] = "World";

    strcat(s1, s2);

    printf("%s\n", s1);

    return 0;
}

10. String Compare

#include <stdio.h>
#include <string.h>

int main() {
    char s1[] = "abc";
    char s2[] = "abc";

    printf("%d\n", strcmp(s1, s2));

    return 0;
}