create a1

a1/program.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <string.h>
+
+#define MAX_LENGTH 100
+
+int isMatchingPair(char open, char close)
+{
+    return (open == '(' && close == ')') || (open == '{' && close == '}') || (open == '[' && close == ']') || (open == '<' && close == '>');
+}
+
+int main()
+{
+    char input[MAX_LENGTH];
+    fgets(input, sizeof(input), stdin);
+    
+    int len = strlen(input);
+    if (input[len - 1] == '\n')
+    {
+        input[len - 1] = '\0';
+        len--;
+    }
+
+    printf("Read: %s\n", input);
+
+    char stack[MAX_LENGTH];
+
+    int top = -1;
+
+    for (int i = 0; i < len; i++)
+    {
+        char ch = input[i];
+        if (ch == '(' || ch == '{' || ch == '[' || ch == '<')
+        {
+            stack[++top] = ch;
+        }
+        else if (ch == ')' || ch == '}' || ch == ']' || ch == '>')
+        {
+            if (top == 0)
+            {
+                printf("Crossed bracket %c in %d, expected opening bracket\n", ch, i);
+                return 0;
+            }
+            else if (!isMatchingPair(stack[top], ch))
+            {
+                printf("Crossed bracket %c in %d, expected %c\n", ch, i, (stack[top] == '(' ? ')' : stack[top] == '{' ? '}' : stack[top] == '[' ? ']' : '>'));
+                return 0;
+            }
+            top--;
+        }
+    }
+
+    if (top != -1)
+    {
+        printf("Unmatched opening bracket %c\n", stack[top]);
+        return 0;
+    }
+
+    printf("All brackets OK\n");
+    return 0;
+}