putchar is a function in the C programming language that writes a single character to the standard output stream, stdout.[1] Its prototype is as follows:

int putchar (int character)

The character to be printed is fed into the function as an argument, and if the writing is successful, the argument character is returned. Otherwise, end-of-file is returned.

The putchar function is specified in the C standard library header file stdio.h.

Sample usage

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The following program uses getchar to read characters into an array and print them out using the putchar function after an end-of-file character is found.

 #include <stdio.h>

 int main(void)
 {
   char str[1000];
   int ch, i, n = 0;
  
   while ((ch = getchar()) != EOF && n < 1000)
     str[n++] = ch;
	   
   for (i = 0; i < n; ++i)
     putchar(str[i]);

   putchar('\n'); /* trailing '\n' needed in Standard C */
	
   return 0;
 }

The program specifies the reading length's maximum value at 1000 characters. It will stop reading either after reading 1000 characters or after reading in an end-of-file indicator, whichever comes first.

References

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  1. ISO/IEC 9899:1999 specification (PDF). p. 299, § 7.19.7.9.
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