commit 3daef3921999e64e12c06e6fdf17724ea2bc1d92
parent cfccdaf1eaae4e85d23662ea8ebe66be47023e2a
Author: Amit Dutta <amitdutta4255@gmail.com>
Date: Wed, 8 Oct 2025 12:11:24 +0530
new 31 with logic
Diffstat:
2 files changed, 142 insertions(+), 0 deletions(-)
diff --git a/letusc/luc031-logic.c b/letusc/luc031-logic.c
@@ -0,0 +1,100 @@
+/* Write a program to enter numbers till the user wants. At the end it
+should display the count of positive, negative and zeros entered. */
+/* Author - Amit Dutta, Date - 8th OCT, 2025 */
+/* Let Us C, Chap- 5, Page - 87, Qn No.: B(d) */
+
+/*
+ * DETAILED PROGRAM PLAN:
+ * 1. INITIALIZATION: Set three counters (positive_count, negative_count, zero_count) to zero.
+ * 2. INPUT LOOP: Start an infinite loop to continuously request user input.
+ * 3. READ INPUT: Use fgets() to read the user's input as a generic string (char array).
+ * This allows the program to accept multi-digit numbers (e.g., "-500") or the command ('n').
+ * 4. TERMINATION CHECK: Immediately check if the input string is exactly "n" using strcmp().
+ * If true, the user wants to quit, so break the loop.
+ * 5. VALIDATION & CONVERSION: If the input is not "n", use sscanf() to safely attempt to convert
+ * the string into an integer.
+ * 6. COUNTING LOGIC: If sscanf() successfully reads an integer (sscanf returns 1):
+ * - If the number is > 0, increment positive_count.
+ * - If the number is < 0, increment negative_count.
+ * - If the number is == 0, increment zero_count.
+ * 7. ERROR HANDLING: If the input is neither "n" nor a valid number (sscanf returns 0),
+ * inform the user of invalid input and continue the loop.
+ * 8. FINAL DISPLAY: After the loop terminates, print the final totals for positive, negative, and zero counts.
+ */
+
+#include <stdio.h>
+#include <stdlib.h> // for strtol
+#include <string.h> // for strcmp
+
+// Maximum size of the input line
+#define MAX_INPUT_LEN 15
+
+int main() {
+ // Initialize counters
+ int positive_count = 0;
+ int negative_count = 0;
+ int zero_count = 0;
+
+ // Buffer to store the user's input as a string (e.g., "123", "-50", or "n")
+ char input_buffer[MAX_INPUT_LEN];
+ int number;
+
+ printf("--- Number Analyzer ---\n");
+ printf("Enter numbers one by one. Type 'n' and press Enter to finish.\n\n");
+
+ // Loop until the user enters 'n'
+ while (1) {
+ printf("Enter number or 'n': ");
+
+ // Read the entire line of input into the buffer
+ if (fgets(input_buffer, MAX_INPUT_LEN, stdin) == NULL) {
+ // Handle EOF (end of file) or reading error
+ break;
+ }
+
+ // Remove the trailing newline character from the input_buffer
+ // The last character will be '\n' if the input was shorter than MAX_INPUT_LEN
+ size_t len = strlen(input_buffer);
+ if (len > 0 && input_buffer[len - 1] == '\n') {
+ input_buffer[len - 1] = '\0';
+ }
+
+ // 1. Check for the termination condition
+ if (strcmp(input_buffer, "n") == 0) {
+ printf("\n'n' received. Stopping input...\n");
+ break; // Exit the while loop
+ }
+
+ // 2. Attempt to convert the input string to an integer
+ // sscanf attempts to read the string according to the format "%d" (decimal integer)
+ // It returns 1 if a number was successfully read.
+ int conversions = sscanf(input_buffer, "%d", &number);
+
+ if (conversions == 1) {
+ // Conversion was successful, now check the number's sign
+ if (number > 0) {
+ positive_count++;
+ } else if (number < 0) {
+ negative_count++;
+ } else {
+ zero_count++;
+ }
+ printf(" -> Number recorded: %d\n", number);
+ } else {
+ // Conversion failed. The input was neither 'n' nor a valid integer.
+ printf(" -> Invalid input. Please enter a valid number or 'n'.\n");
+ }
+ }
+
+ // Display the final results
+ printf("\n====================================\n");
+ printf(" Analysis Complete\n");
+ printf("====================================\n");
+ printf("Positive numbers entered: %d\n", positive_count);
+ printf("Negative numbers entered: %d\n", negative_count);
+ printf("Zeroes entered: %d\n", zero_count);
+ printf("Total numbers recorded: %d\n", positive_count + negative_count + zero_count);
+ printf("====================================\n");
+
+ return 0;
+}+
\ No newline at end of file
diff --git a/letusc/luc031.c b/letusc/luc031.c
@@ -0,0 +1,40 @@
+/* Write a program to enter numbers till the user wants. At the end it
+should display the count of positive, negative and zeros entered. */
+/* Author - Amit Dutta, Date - 8th OCT, 2025 */
+/* Let Us C, Chap- 5, Page - 87, Qn No.: B(d) */
+
+#include <stdio.h>
+int main()
+{
+ int choice = 1, num, positive_count = 0, negative_count = 0, zero_count = 0;
+ while (choice == 1)
+ {
+ printf("\nEnter the number (Type any character and press Enter to finish.) : ");
+ choice = scanf("%d", &num); // Checking whether the user has input any characters
+ if (choice == 1)
+ {
+ printf("Number recorded : %d", num);
+ if (num < 0)
+ negative_count++;
+ else if (num > 0)
+ positive_count++;
+ else if (num == 0)
+ zero_count++;
+ }
+ else
+ {
+ // If the user inputs any characters, then choice = 0, it means he doesn't want to give any more input;
+ choice = 0;
+ printf("\nCharacter received. Stopping input...\n");
+ }
+ }
+ // Display the final results
+ printf("\n====================================\n");
+ printf(" Analysis Complete\n");
+ printf("====================================\n");
+ printf("Positive numbers entered: %d\n", positive_count);
+ printf("Negative numbers entered: %d\n", negative_count);
+ printf("Zeroes entered: %d\n", zero_count);
+ printf("Total numbers recorded: %d\n", positive_count + negative_count + zero_count);
+ printf("====================================\n");
+}+
\ No newline at end of file
