adapted from
Differences Between C and C++
by Robert Niemann (Century College)
11/22/2015

• printf() reference
• scanf() reference

example01.c

#include <stdio.h>
 
int main()
{
    int num;
 
    printf( "Please enter a number: " );
    scanf( "%d", &num );
    printf( "You entered %d", num );
 
    return 0;
}

example02.c

#include <stdio.h>
 
main()
{
  int dec = 5;
  char str[] = "abc";
  char ch = 's';
  float pi = 3.14;
 
  printf("%d %s %f %c\n", dec, str, pi,  ch);
}

example03.c

#include <stdio.h>
 
main()
{
    char ch;
    int x;
    double y;
 
    printf("Enter a character, an integer, and a double:\n");
    scanf("%c %d %lf", &ch, &x, &y);
    printf("%c %d %lf\n", ch, x, y);
}

• fopen() reference

example04.c

/* Writing a text file. */
#include <stdio.h>
 
int main()
{
    FILE *ptr_file;
    int x;
 
    ptr_file =fopen("output.txt", "w");
 
    if (!ptr_file)
        return 1;
 
    for (x = 1; x <= 10; x++)
        fprintf(ptr_file,"%d\n", x);
 
    fclose(ptr_file);
 
    return  0;
}

example05.c

/* Reading a text file. */
#include <stdio.h>
 
int main()
{
    FILE *ptr_file;
    char buf[1000];
 
    ptr_file =fopen("input.txt","r");
    if (!ptr_file)
            return 1;
 
    while (fgets(buf,1000, ptr_file)!=NULL)
            printf("%s",buf);
 
    fclose(ptr_file);
    return 0;
}