我想计算从2月到1月或12月到7月的月份,如何重复遍历数组以获取从2月到1月或12月到7月的计算月份。
char * months[] = {"Jan", "Feb", "Mar", "April", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
char start_m[5];
char end_m[5];
float bill, rate;
float total;
scanf("%s %s %f %f",start_m, end_m,&bill, &rate);
int i, start, end;
for(i = 0; i < 12; i++){
if(strcmp(months[i], start_m) == 0){
start = i;
}
if(strcmp(months[i], end_m) == 0){
end = i;
}
}
if(end < start) {
for(i = start; i < start - end; i++){
total += (bill * rate);
}
} else {
for(i = start; i < end; i++){
total += (bill * rate);
}
}
total += bill;
printf("%.2f", total);
答案 0 :(得分:2)
您可以将模块操作与表达式 pos % size
一起使用。一个例子:
int main()
{
char * months[] = {"Jan", "Feb", "Mar", "April", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
int size = 12;
int start = 1;
for(int i = start; i < start + size; i++)
printf("%d %s\n",i % size, months[i % size]);
return 0;
}
输出:
1 Feb
2 Mar
3 April
4 May
5 Jun
6 Jul
7 Aug
8 Sep
9 Oct
10 Nov
11 Dec
0 Jan
这是有效的,因为对于 0 <= i < size
,表达式 i % size
返回 i
。对于 i = 大小,返回 0,对于 i = 大小 + 1 返回 1,依此类推。