Question

Part I) Write a program that copies one file to another, replacing all lowercase characters with their uppercase equivalents. Part II) Write a program that merges lines alternately from two files and writes the results to a third file. If one file has less lines than the other, then the remaining lines from the larger file should be printed to the screen. Using C language

Answer 1

For first program

#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
int main()
{
      FILE *fp1, *fp2;
      char ch;
      fp1 = fopen("small.txt", "r");
      if (fp1 == NULL)
      {
            puts("File does not exist..");
            exit(1);
      }
      fp2 = fopen("capital.txt", "w");
      if (fp2 == NULL)
      {
            puts("File does not exist..");
            fclose(fp1);
            exit(1);
      }
      while((ch=fgetc(fp1))!=EOF)
      {
            ch = toupper(ch);
            fputc(ch,fp2);
      }
      printf("File successfully copied");
      return 0;
}

For Second program:-

#include <stdio.h>
#include <stdlib.h>
  
int main()
{
  
FILE *fp1 = fopen("first.txt", "r");
FILE *fp2 = fopen("second.txt", "r");
  
// Open file to store the result
FILE *fp3 = fopen("third.txt", "w");
char c;
  
if (fp1 == NULL || fp2 == NULL || fp3 == NULL)
{
puts("Files missing");
exit(0);
}
  

while ((c = fgetc(fp1)) != EOF)
fputc(c, fp3);
  

while ((c = fgetc(fp2)) != EOF)
fputc(c, fp3);
  
fclose(fp1);
fclose(fp2);
fclose(fp3);
return 0;
}

I have attached the screenshots please check