how to take input and output from standard input and outpue code example

Example 1: read from stdin c

#include <stdio.h>
int main( ) {

   char str[100];
   int i;

   printf( "Enter a value :");
   scanf("%s %d", str, &i);

   printf( "\nYou entered: %s %d ", str, i);

   return 0;
}

Example 2: read a document from console in c

#include<stdio.h>
int main(int argc,char *argv[]){
	FILE *in=fopen(*++argv,"r");
	char c;
	while((c=fgetc(in))!=EOF)
		putchar(c);
	fclose(in);
	return 0;
}