Home » C programs » C string programs

C program to convert a string to sentence case

In this C program, we are going to learn how to convert a given string to sentence case? To implement this logic, we are creating a user define function to do the same.
Submitted by IncludeHelp, on April 05, 2018

So, first of all, we have to understand - what is a sentence case? A string is in a sentence case, if first character of each sentence is an uppercase character.

Problem statement

Given a string and we have to convert it to sentence case using C program.

Example

Input string: "hello how are you?"
Output:
Sentence case string is: "Hello how are you?"

Input string: "hello. how are you?"
Output:
Sentence case string is: "Hello. How are you?"

Program to convert string to sentence case in C

#include <stdio.h>
#include <string.h>

// function to convert string to sentence case
void StrToSentence(char* string) {
  int length = 0, i = 0;

  length = strlen(string);

  for (i = 0; i < length; i++) {
    if ((i == 0) && (string[i] >= 'a' && string[i] <= 'z')) {
      string[i] = string[i] - 32;
    } else if (string[i] == '.') {
      if (string[i + 1] == ' ') {
        if (string[i + 2] >= 'a' && string[i + 2] <= 'z') {
          string[i + 2] = string[i + 2] - 32;
        }
      } else {
        if (string[i + 1] >= 'a' && string[i + 1] <= 'z') {
          string[i + 1] = string[i + 1] - 32;
        }
      }
    }
  }
}

// main function
int main() {
  char string[50] = {0};
  int length = 0, i = 0, j = 0, k = 0;

  printf("\nEnter the string : ");
  gets(string);

  // pass the string to the function
  StrToSentence(string);

  printf("Final string is : %s", string);
  return 0;
}

Output

Run 1: 
Enter the string : hello world. how are you?
Final string is : Hello world. How are you?

Run 2:
Enter the string : hello.how are you? 
Final string is : Hello.How are you?

C String Programs »