[dywang@deyu zzz]$ vim forcontinus1.c
[dywang@deyu zzz]$ cat forcontinus1.c
#include <stdio.h>
int main() {
int i, a, sum=1;
printf("Enter an integer: ");
scanf("%d", &a);
printf("1");
for ( i=2; i<a; i++) {
if (!(i%4)) continue;
printf("+%d", i);
sum += i;
}
printf("=%d\n", sum);
}
[dywang@deyu zzz]$ gcc -o forcontinus1 forcontinus1.c
[dywang@dywIssd zzz]$ ./forcontinus1 Enter an integer: 13 1+2+3+5+6+7+9+10+11=54 [dywang@dywIssd zzz]$ ./forcontinus1 Enter an integer: 12 1+2+3+5+6+7+9+10+11=54 [dywang@dywIssd zzz]$ ./forcontinus1 Enter an integer: 7 1+2+3+5+6=17