下面是用函数指针实现的三角函数表，其中cos函数、sin函数和tan函数都已经在<math.h>中定义，函数tabulate中使用的函数ceil也属于<math.h>，当给定double型实参x时，函数ceil会返回大于或等于x的最小整数。当给定三角函数的起始值，终止值和步长以后，程序会打印出相对应的三角函数值。
#include <math.h>
#include <stdio.h>
// 传递函数指针f时，tabulate函数显示函数f的值
void tabulate(double (*f)(double), double first, double last, double incr);
int main(void)
{
double initial, final, increment;
printf("Enter initial value: ");
scanf("%lf", &initial);
printf("Enter final value: ");
scanf("%lf", &final);
printf("Enter increment: ");
scanf("%lf", &increment);
printf("\n x cos(x)"
"\n ------- -------\n");
tabulate(cos, initial, final, increment);
printf("\n x sin(x)"
"\n ------- -------\n");
tabulate(sin, initial, final, increment);
printf("\n x tan(x)"
"\n ------- -------\n");
tabulate(tan, initial, final, increment);
return 0;
}
void tabulate(double (*f)(double), double first, double last, double incr)
{
double x;
int i, num_intervals;
num_intervals = ceil((last - first) / incr);
for (i = 0; i <= num_intervals; i++) {
x = first + i * incr;
printf("%10.5f %10.5f\n", x, (*f)(x));
}
}
参考资料：
《C语言程序设计现代方法》
