C语言输出循环类内的指定的数值和变量前感叹号！的使用

先定义全局的变量和类型，该方法只输出循环的最后一个值。

int J

源码

#include <stdio.h> #define SIZE 4 int J; int a[SIZE] = {1, 2, 3, 4}; int b[SIZE] = {1, 3, 5, 6}; int i; int main() { for (i = 0; i < SIZE; i++) { J = 2; // printf("a(%d) - b(%d) = %d \n", i, i, a[i] - b[i]); } printf("J================%d\n",J); return 0; }

执行结果：

J================:2 [Thread 9428.0x4c10 exited with code 0] [Inferior 1 (process 9428) exited normally]

感叹号

#include <stdio.h> #define SIZE 4 int J; int a[SIZE] = {1, 2, 3, 4}; int b[SIZE] = {1, 3, 5, 6}; int i; int main() { int R; for (i = 0; i < SIZE; i++) { if (!a[i] < 3) { J = a[i]; } R = 20; // printf("a(%d) - b(%d) = %d \n", i, i, a[i] - b[i]); } printf("J================%d\n", J); printf("R================%d\n", R); return 0; }

执行结果：

J================4 R================20 [Thread 25636.0xb9e0 exited with code 0] [Inferior 1 (process 25636) exited normally]