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Revision as of 12:15, 11 March 2006
putchar is a function in C programming language that writes a single character to the standard output. 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. It has an alias: fputchar.
Sample usage
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() {
char str;
int n = 0;
while (!feof(stdin)) {
str = getchar();
++n;
}
for (int i = 0; i < n; ++i) {
putchar(str);
}
return 0;
}
The function specifies the reading length's maximum value at 1000 characters; however if the end-of-file character doesn't come up after 1000 characters are read, different operating systems and different compilers will give different results: Some cases will terminate the program at a segmentation fault, while some others will read the remaining string into the non-allocated area of the memory, possibly causing errors to other programs.