C语言学习笔记之数组运算

Array Calculation

数组计算

Array Calculation

Intergrated initialization of arrays

int a[] = {2,4,5,6,7};

• give the initial value of all elements of the array by directly using “{}”
• don’t need to give how large the array is, because the compiler will help you count.

locate Intergrated initialization

postscript: only C99

int a[10] = {
	[0] = 2, [2] = 3, 6 ,
};

• locate initial data by [n]
• data have no located will attach it to the back of front
• other location will assign zero(0)

size of array

array assignment

full of source code

#include <stdio.h>
int search(int key, int a[], int length);

int main(void)
{
	int a[] = {2,3,4,6,1,0,8};
	int x;
	int loc;
	scanf("%d", &x);
	loc = search(x, a, sizeof(a)/sizeof(a[0]));
	if (loc != -1){
		printf("%d在%d这里\n", x, loc);
	} else {
		printf("%d不存在", x);
	}
	return 0;
}
int search(int key, int a[], int length)
{
	int ret = -1;
	int i;
	for (i = 0; i < length; i++)
	{

		if (a[i] == key) {
			ret = i;
			break;
		}
	}
	return ret;
}

An example for Array Calculation

determine prime number