Add 3

.vscode/launch.json

@@ -0,0 +1,32 @@
+{
+    "configurations": [
+        {
+            "name": "C/C++: gcc build and debug active file",
+            "type": "cppdbg",
+            "request": "launch",
+            "program": "${fileDirname}/${fileBasenameNoExtension}",
+            "args": [],
+            "stopAtEntry": false,
+            "cwd": "${fileDirname}",
+            "environment": [],
+            "externalConsole": false,
+            "MIMode": "gdb",
+            "setupCommands": [
+                {
+                    "description": "Enable pretty-printing for gdb",
+                    "text": "-enable-pretty-printing",
+                    "ignoreFailures": true
+                },
+                {
+                    "description": "Set Disassembly Flavor to Intel",
+                    "text": "-gdb-set disassembly-flavor intel",
+                    "ignoreFailures": true
+                }
+            ],
+            "preLaunchTask": "C/C++: gcc build active file",
+            "miDebuggerPath": "/usr/bin/gdb",
+            "internalConsoleOptions": "neverOpen"
+        }
+    ],
+    "version": "2.0.0"
+}

.vscode/tasks.json

@@ -0,0 +1,25 @@
+{
+    "tasks": [
+        {
+            "type": "cppbuild",
+            "label": "C/C++: gcc build active file",
+            "command": "/usr/bin/gcc",
+            "args": [
+                "-fdiagnostics-color=always",
+                "-g",
+                "${file}",
+                "-o",
+                "${fileDirname}/${fileBasenameNoExtension}"
+            ],
+            "options": {
+                "cwd": "${fileDirname}"
+            },
+            "problemMatcher": [
+                "$gcc"
+            ],
+            "group": "build",
+            "detail": "Task generated by Debugger."
+        }
+    ],
+    "version": "2.0.0"
+}

3/fabo.c

@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]) {
+	int n, i;
+	long long a = 0, b = 1, c;
+
+	// 从命令行参数或键盘获取n
+	if (argc > 1) {
+		n = atoi(argv[1]);
+	}
+	else {
+		printf("请输入一个整数: ");
+		scanf("%d", &n);
+	}
+
+	// 验证输入
+	if (n <= 0) {
+		printf("请输入一个正整数\n");
+		return 1;
+	}
+
+	// 生成并输出斐波那契数列的前n项
+	printf("%lld\n", a); // 第1项: 0
+	if (n > 1) {
+		printf("%lld\n", b); // 第2项: 1
+	}
+
+	for (i = 3; i <= n; i++) {
+		c = a + b;
+		printf("%lld\n", c);
+		a = b;
+		b = c;
+	}
+
+	return 0;
+}

3/faboexec.c

@@ -0,0 +1,83 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <string.h>
+
+int main(int argc, char *argv[]) {
+	int pipefd[2]; // 管道文件描述符
+	pid_t pid;
+	int status;
+	char buf[1024];
+	long long sum = 0;
+	long long num;
+
+	// 获取输入n
+	int n;
+	if (argc > 1) {
+		n = atoi(argv[1]);
+	}
+	else {
+		printf("请输入一个整数: ");
+		scanf("%d", &n);
+	}
+
+	// 创建管道
+	if (pipe(pipefd) == -1) {
+		perror("pipe");
+		exit(EXIT_FAILURE);
+	}
+
+	// 创建子进程
+	pid = fork();
+
+	if (pid < 0) { // 创建子进程失败
+		perror("fork");
+		exit(EXIT_FAILURE);
+	}
+	else if (pid == 0) { // 子进程
+		// 关闭管道读端
+		close(pipefd[0]);
+
+		// 将标准输出重定向到管道写端
+		dup2(pipefd[1], STDOUT_FILENO);
+		close(pipefd[1]);
+
+		// 执行fabo程序，传入参数n
+		char n_str[20];
+		sprintf(n_str, "%d", n);
+		execl("./fabo", "fabo", n_str, NULL);
+
+		// 如果execl失败，则执行下面的代码
+		perror("execl");
+		exit(EXIT_FAILURE);
+	}
+	else { // 父进程
+		// 关闭管道写端
+		close(pipefd[1]);
+
+		// 从管道读取子进程输出的每个斐波那契数，并计算总和
+		FILE *fp = fdopen(pipefd[0], "r");
+		if (fp == NULL) {
+			perror("fdopen");
+			exit(EXIT_FAILURE);
+		}
+
+		while (fgets(buf, sizeof(buf), fp) != NULL) {
+			num = strtoll(buf, NULL, 10);
+			sum += num;
+		}
+
+		// 关闭文件和管道读端
+		fclose(fp);
+
+		// 等待子进程结束
+		waitpid(pid, &status, 0);
+
+		// 打印总和
+		printf("斐波那契数列前%d项的总和为: %lld\n", n, sum);
+	}
+
+	return 0;
+}