UNIT-V PROGRAMS

Unit-V: Dynamic Memory Allocation & File Handling Operations

1. Program to Copy Content of One File into Another

• Purpose: To copy contents from one file (Input.txt) to another.

• Code:

  #include <stdio.h>
  int main(){  
      FILE *fptr1, *fptr2;  
      char c;  
      // Open one file for reading  
      fptr1 = fopen("Input.txt", "r");  
      fptr2 = fopen("filename", "w");  
      // Read contents from file  
      c = fgetc(fptr1);  
      while (c != EOF){   
          fputc(c, fptr2);   
          c = fgetc(fptr1);  
      }  
      fclose(fptr1);  
      fclose(fptr2);  
      return 0;  
  }

2. Program to Count Number of Words and Characters in a File

• Purpose: To calculate total characters, words, and lines in test.txt.

• Code:

  #include <stdio.h>
  int main() {  
      FILE *file;   
      char ch;  
      int characters, words, lines;  
      /* Open source files in 'r' mode */   
      file = fopen("test.txt", "r");  
      characters = words = lines = 0;  
      while ((ch = fgetc(file)) != EOF) {  
          characters++;  
          /* Check new line */  
          if (ch == '\n' || ch == '\0')  
              lines++;  
          /* Check words */  
          if (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\0')  
              words++;  
      }  
      /* Increment words and lines for last word */   
      if (characters > 0) {  
          words++;  
          lines++;  
      }  
      /* Print file statistics */  
      printf("\n");  
      printf("Total characters = %d\n", characters);  
      printf("Total words  = %d\n", words);  
      printf("Total lines  = %d\n", lines);  
      /* Close files to release resources */   
      fclose(file);   
      return 0;  
  }

3. Program to Implement malloc()

• Purpose: To allocate memory dynamically for n integers.

• Code:

  #include<stdio.h>  
  #include<stdlib.h>  
  void main() {  
      int *ptr, n, i;  
      printf("Enter how many numbers you want to enter");  
      scanf("%d", &n);  
      ptr = (int *) malloc(n * sizeof(int));  
      for (i=0; i<n; i++) {  
          scanf("%d", ptr+i);  
      }  
      for (i=0; i<n; i++) {  
          printf("%d", *(ptr+i));  
      }  
  }

4. Program to Implement calloc()

• Purpose: To allocate memory dynamically and initialize memory to zero for n integers.

• Code:

  #include<stdio.h>  
  #include<stdlib.h>  
  void main() {  
      int *ptr, n, i;  
      printf("Enter how many numbers you want to enter");  
      scanf("%d", &n);  
      ptr = (int *) calloc(n , sizeof(int));  
      for (i=0; i<n; i++) {  
          scanf("%d", ptr+i);  
      }  
      for (i=0; i<n; i++) {  
          printf("%d", *(ptr+i));  
      }  
  }