C Language Jump Statements Using break and continue
Example
Immediately continue reading on invalid input or break on user request or end-of-file:
#include <stdlib.h> /* for EXIT_xxx macros */
#include <stdio.h> /* for printf() and getchar() */
#include <ctype.h> /* for isdigit() */
void flush_input_stream(FILE * fp);
int main(void)
{
int sum = 0;
printf("Enter digits to be summed up or 0 to exit:\n");
do
{
int c = getchar();
if (EOF == c)
{
printf("Read 'end-of-file', exiting!\n");
break;
}
if ('\n' != c)
{
flush_input_stream(stdin);
}
if (!isdigit(c))
{
printf("%c is not a digit! Start over!\n", c);
continue;
}
if ('0' == c)
{
printf("Exit requested.\n");
break;
}
sum += c - '0';
printf("The current sum is %d.\n", sum);
} while (1);
return EXIT_SUCCESS;
}
void flush_input_stream(FILE * fp)
{
size_t i = 0;
int c;
while ((c = fgetc(fp)) != '\n' && c != EOF) /* Pull all until and including the next new-line. */
{
++i;
}
if (0 != i)
{
fprintf(stderr, "Flushed %zu characters from input.\n", i);
}
}
