<C Primer Plus>8 The if statement
1 #include <stdio.h>
2 #include <math.h>
3 int main(void){
4 const int FREESEING = 0;
5 float temperature;
6 int cold_days = 0;
7 int all_days = 0;
8
9 printf("Please input the temperature:\n");
10 printf("q is quit.\n");
11 while (1 == scanf("%f", &temperature)){
12 all_days++;
13 if (temperature < FREESEING){
14 cold_days++;
15 }
16 }
17 if (all_days != 0){
18 printf("The number of all_days = :%d ", all_days);
19 printf("The cold day = %d \n", cold_days);
20 printf("the cold day %.2f%% of all day.\n", 100.0*(float)cold_days / all_days);
21 }
22 else{
23 printf("input no data.\n");
24 }
25
26 return 0;
27 }
if (expression)
statement
