第一个for循环里面的两个%%是什么意思呢？

#include

#define NUM_RATES ((int) (sizeof(value) / sizeof(value[0])))
#define INITIAL_BALANCE 100.00

int main(void)
{
int i, low_rate, num_years, year;
double value[5];

printf("Enter interest rate: ");
scanf("%d", &low_rate);
printf("Enter number of years: ");
scanf("%d", &num_years);

printf("\nYears");
for (i = 0; i < NUM_RATES; i++) {
printf("%6d%%", low_rate + i);
value[i] = INITIAL_BALANCE;
}
printf("\n");

for (year = 1; year <= num_years; year++) {
printf("%3d ", year);
for (i = 0; i < NUM_RATES; i++) {
value[i] += (low_rate + i) / 100.0 * value[i];
printf("%7.2f", value[i]);
}
printf("\n");
}

return 0;
}

因为%是格式化字符串，它后面的字符代表格式，那么要输出%本身，它是需要转义的，%%就是直接输出一个%的意思