Question

getchar() redirect to input textfile in ASCI C programming.

Hello, underneath is the code I did and it works. However, my professor is asking to use getchar() and have an input text file to redirect it. How would i do that on my code? Thank you for the help.

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

int main()
{
char string[100];
int c = 0, Lcase[26] = {0}, x;
int Ucase[26] = {0};
  

printf("Enter a string\n");
gets(string);

while (string[c] != '\0')
{
if (string[c] >= 'a' && string[c] <= 'z')
   {
x = string[c] - 'a';
Lcase[x]++;
}
   if( string[c] >= 'A' && string[c] <= 'Z')
   {
       x = string[c] - 'A';
       Ucase[x]++;  
   }
c++;
}

for (c = 0; c < 26; c++)
{
printf("%c occurs %d times in the string.\n", c + 'a', Lcase[c]);
}
for (c = 0; c < 26; c++)
{
       printf("%c occurs %d times in the string.\n", c + 'A', Ucase[c]);
}
return 0;

}

Answer 1

Using getchar() function, you can read the data from console(stdin) as follows:

while(((ch=getchar()) != EOF))

{

.................

}

Reading data from file:

while((ch = fgetc(fp)) != EOF)
{

...............

}

Program:

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

int main()
{
FILE *fp;
char ch;
char string[100];
int c = 0, Lcase[26] = {0}, x;
int Ucase[26] = {0};

//Opening file for reading
fp = fopen("ipData.txt", "r");

//Checking file
if(fp == NULL)
{
printf(" File doesn't Exist... ");
return 0;
}

//Reading data from stdin using getchar
//while(((ch=getchar()) != EOF))

//Reading data from file
while((ch = fgetc(fp)) != EOF)
{
if (ch >= 'a' && ch <= 'z')
{
x = ch - 'a';
Lcase[x]++;
}
if( ch >= 'A' && ch <= 'Z')
{
x = ch - 'A';
Ucase[x]++;
}
c++;
}

for (c = 0; c < 26; c++)
{
printf("%c occurs %d times in the string. ", c + 'a', Lcase[c]);
}
for (c = 0; c < 26; c++)
{
printf("%c occurs %d times in the string. ", c + 'A', Ucase[c]);
}

//Closing file
fclose(fp);

return 0;
}

Sample Run: