C PROGRAMMING PROGRAM • SWITCH & MENU PROGRAMS

Build a Simple Banking Menu Using switch

Learn how to build a simple banking menu using switch using a clear C program.

IntermediateswitchBalance updateValidation

PROBLEM UNDERSTANDING

Input and expected output

Sample input

1
250

Sample output

Balance = 1250.00

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int choice;
    double balance = 1000.0, amount;
    printf("1. Deposit  2. Withdraw  3. Balance\nChoose: ");
    scanf("%d", &choice);
    switch (choice) {
        case 1:
            printf("Enter amount: "); scanf("%lf", &amount);
            if (amount > 0) balance += amount;
            else { puts("Invalid amount."); return 0; }
            break;
        case 2:
            printf("Enter amount: "); scanf("%lf", &amount);
            if (amount > 0 && amount <= balance) balance -= amount;
            else { puts("Invalid amount or insufficient balance."); return 0; }
            break;
        case 3: break;
        default: puts("Invalid choice."); return 0;
    }
    printf("Balance = %.2f\n", balance);
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Balance = 1250.00

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PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Select one banking operation, validate its amount and update the balance safely.
Display the computed result.

Select one banking operation, validate its amount and update the balance safely.

EFFICIENCY

Time and space complexity

Time complexity

O(1)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

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Use the correct format specifier for every variable.

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Initialize variables before using their values.

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Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.