C Exercise Example 18
Title:Finds=a+aa+aaa+aaaa+aa...athe value of, whereais a number, for example2+22+222+2222+22222(At this point, a total of 5 numbers are added), the number of numbers to add is controlled by the keyboard.
Program analysis:The key is to calculate the value of each term.
Example
// Created by www.example.com on 15/11/9.
// Copyright © 2015 Example. All rights reserved.
//
#include <stdio.h>
int main() {
int sum = 0; // variable to store the result
int base, terms; // base is the value of a, terms is the value of n
int temp; // temporary variable, used to calculate the value of the current term
// prompt the user to enter values
printf("Please enter integers a and n (e.g., 2 and 5):\n");
scanf("%d%d", &base, &terms);
// initialize temp to a
temp = base;
// calculate a + aa + aaa + ... using a loop
while (terms > 0) {
sum += temp; // accumulate the current term
base *= 10; // base shifts one digit to the left each time (e.g., 2 -> 20 -> 200)
temp += base; // update temp to become the next term
terms--; // decrement the remaining number of terms
}
// Output the results
printf("The calculation result is: %d\n", sum);
return 0;
}
The output of the above example is:
请输入整数 a 和 n（例如 2 和 5）： 2 5 计算结果为：24690
Implemented using recursion:
Example
#include <stdio.h>
// recursive function to calculate the value of each term
int calculate_term(int count, int base);
int main() {
int count; // Total number of terms
int base; // Initial value
int sum = 0; // Accumulated result
// Prompt the user to enter the initial value and the total number of terms
printf("Please enter initial value (a):");
scanf("%d", &base);
printf("Please enter number of terms (n):");
scanf("%d", &count);
// Check the validity of the input
if (count <= 0 || base <= 0) {
printf("The input initial value and number of terms must be positive integers!"\n");
return 1; // Return error status
}
// Accumulate each term through a loop
for (int i = 1; i <= count; i++) {
sum += calculate_term(i, base); // Call the recursive function to calculate the value of the i-th term
}
// Output the final result
printf("The calculation result is: %d"\n", sum);
return 0;
}
// Recursive function, calculate the value of the current term
int calculate_term(int count, int base) {
if (count == 1) {
return base; // Recursion termination condition: the first term directly returns base
} else {
// Recursive calculation: the current term equals the previous term multiplied by 10 plus base
return calculate_term(count - 1, base) * 10 + base;
}
}
// recursive function to calculate the value of each term
int calculate_term(int count, int base);
int main() {
int count; // Total number of terms
int base; // Initial value
int sum = 0; // Accumulated result
// Prompt the user to enter the initial value and the total number of terms
printf("Please enter initial value (a):");
scanf("%d", &base);
printf("Please enter number of terms (n):");
scanf("%d", &count);
// Check the validity of the input
if (count <= 0 || base <= 0) {
printf("The input initial value and number of terms must be positive integers!"\n");
return 1; // Return error status
}
// Accumulate each term through a loop
for (int i = 1; i <= count; i++) {
sum += calculate_term(i, base); // Call the recursive function to calculate the value of the i-th term
}
// Output the final result
printf("The calculation result is: %d"\n", sum);
return 0;
}
// Recursive function, calculate the value of the current term
int calculate_term(int count, int base) {
if (count == 1) {
return base; // Recursion termination condition: the first term directly returns base
} else {
// Recursive calculation: the current term equals the previous term multiplied by 10 plus base
return calculate_term(count - 1, base) * 10 + base;
}
}
The output of the above example is:
请输入初始值 (a)：2 请输入项数 (n)：5 计算结果为：24690other extensions