c how to write variables to file code example

Example: how to take inputs and give outputs from a file in c

#include<stdio.h>

int main()
{
    FILE *fp;
    char ch;
    fp = fopen("one.txt", "w");
    printf("Enter data...");
    while( (ch = getchar()) != EOF) {
        putc(ch, fp);
    }
    fclose(fp);
    fp = fopen("one.txt", "r");
 
    while( (ch = getc(fp)! = EOF)
    printf("%c",ch);
    
    // closing the file pointer
    fclose(fp);
    
    return 0;
}