C语言中的isupper()函数

C编程中的isupper()函数检查给定字符是否为大写。 isupper()函数在ctype.h头文件中定义。
句法 ：

int isupper ( int x );

例子：

Input: A
Output: Entered character is uppercase character
Input: a
Output: Entered character is not uppercase character
Input: 1
Output: Entered character is not uppercase character

// C program to demonstrate
// isupper() function
#include 
#include 
int main()
{
    char ch = 'A';
  
    // checking uppercase
    if (isupper(ch))
        printf("\nEntered character is uppercase character");
    else
        printf("\nEntered character is not uppercase character");
}

输出：

Entered character is uppercase character

应用程序：使用C编程语言中的isupper()函数来找出给定句子中存在的大写字母总数。
例子：

Input: GEEKSFORGEEKS
Output: Number of upper case present in the sentence is : 13
Input: GeeksFORGeeks
Output: Number of upper case present in the sentence is : 5
Input: geeksforgeeks
Output: Number of upper case present in the sentence is : 0

// C program to demonstrate
// isupper() function
  
#include 
#include 
  
// called function
int ttl_upper(int i, int counter)
{
    char ch;
    char a[50] = "GeeksForGeeks";
    ch = a[0];
  
    // counting of upper case
    while (ch != '\0') {
        ch = a[i];
        if (isupper(ch))
            counter++;
  
        i++;
    }
  
    // returning total number of upper case present in sentence
    return (counter);
}
int main()
{
    int i = 0;
    int counter = 0;
  
    // calling function
    counter = ttl_upper(i, counter);
    printf("\nNumber of upper case present in the sentence is : %d", counter);
    return 0;
}

输出：

Number of upper case present in the sentence is : 3

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