添加了软判决和py绘图代码

Author: Yauanyyy

README.md

@@ -13,7 +13,7 @@
 
 - [x] **编码器 (Encoder)**: 完成状态表生成与编码逻辑。
 - [x] **硬判决译码 (Hard Viterbi)**: 完成 Hamming 距离计算与回溯算法。
-- [ ] **软判决译码 (Soft Viterbi)**: 需修改度量计算方式 (Euclidean distance)。
-- [ ] **性能仿真 (Simulation)**: 导出 BER vs SNR 数据并绘图。
+- [x] **软判决译码 (Soft Viterbi)**: 需修改度量计算方式 (Euclidean distance)。
+- [x] **性能仿真 (Simulation)**: 导出 BER vs SNR 数据并绘图。
 - [ ] **(可选) BCJR**
 - [ ] **(可选) Turbo: 进阶任务。**

Viterbi_Hard_K3_75.c

@@ -47,18 +47,31 @@ int main()
 	double BER;//BER代表比特误码率
 	double progress;//progress是用来显示进度的变量
 
+    // --- 定义csv文件指针 ---
+    FILE *fp = NULL; 
+    // 打开hard_viterbi.csv
+    fp = fopen("hard_viterbi.csv", "w"); 
+    if (fp == NULL) {
+        printf("Error: Could not open file for writing.\n");
+        return 1;
+    }
+    // 写入表头
+    fprintf(fp, "SNR,BER\n"); 
+    // -------------------------
+
 	//generate state table 生成状态转移表
 	statetable();
 
 	//random seed
 	srand((int)time(0));
 
 	//input the SNR and frame number
-	printf("\nEnter start SNR: ");
+    printf("\n--- Hard Decision Viterbi Simulation ---\n");
+	printf("Enter start SNR: ");
 	scanf("%f", &start);
-	printf("\nEnter finish SNR: ");
+	printf("Enter finish SNR: ");
 	scanf("%f", &finish);
-	printf("\nPlease input the number of message: ");
+	printf("Please input the number of message: ");
 	scanf("%ld", &seq_num);
 
 	for (SNR = start; SNR <= finish; SNR++)//外层循环，遍历不同的信噪比
@@ -116,17 +129,30 @@ int main()
 
 			//print the intermediate result
 			printf("Progress=%2.1f, SNR=%2.1f, Bit Errors=%ld, BER=%E\r", progress, SNR, bit_error, BER);
+
+
+            
 		}
 
 		//calculate the final BER
 		BER = (double)bit_error / (double)(message_length*seq_num);
 
+        // --- 将结果写入文件 ---
+        // 格式: SNR, BER
+        fprintf(fp, "%f,%E\n", SNR, BER);
+        // 同时在屏幕打印结果
+        printf("SNR=%2.1f, Bit Errors=%ld, BER=%E\n", SNR, bit_error, BER);
+
 		//print the final result
-		printf("Progress=%2.1f, SNR=%2.1f, Bit Errors=%ld, BER=%E\n", progress, SNR, bit_error, BER);
+		//printf("Progress=%2.1f, SNR=%2.1f, Bit Errors=%ld, BER=%E\n", progress, SNR, bit_error, BER);
 	}
 
 	//system("pause");
 
+    // --- 关闭csv文件 ---
+    fclose(fp);
+    printf("Result saved to hard_viterbi.csv\n");
+
     return 0;
 }
 
@@ -296,7 +322,7 @@ void decoder()
         for (int curr_state = 0; curr_state < 4; curr_state++)
         {
             // 如果当前状态不可达，就不用算了
-            if (path_metric[curr_state] == INF) continue;
+            if (path_metric[curr_state] >= INF) continue;
 
             // 遍历所有可能的输入位 (0 或 1)
             for (input = 0; input <= 1; input++)