C PROGRAMMING PROGRAM • STRINGS

Convert a String to Uppercase

Learn how to convert a string to uppercase using a clear C program.

Beginnertoupper()StringsCharacter conversion

PROBLEM UNDERSTANDING

Input and expected output

Sample input

Code Bhavya

Sample output

Uppercase: CODE BHAVYA

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>
#include <ctype.h>

int main(void)
{
    char text[300];

    fgets(text, sizeof text, stdin);
    for (int index = 0; text[index] != '\0'; index++)
        text[index] = (char) toupper((unsigned char) text[index]);
    printf("Uppercase: %s", text);
    return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

Uppercase: CODE BHAVYA

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Apply toupper() to every character while preserving non-alphabetic characters.
Display the computed result.

Apply toupper() to every character while preserving non-alphabetic characters.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

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.